ACT Math : Kites

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #241 : Geometry

A kite has one set of opposite interior angles where the two angles measure \(\displaystyle 44$^{\circ}$\) and \(\displaystyle 59$^{\circ}$\), respectively. Find the measurement for one of the two remaining interior angles in this kite. 

Possible Answers:

\(\displaystyle 128.5$^{\circ}$\)

\(\displaystyle 130.5$^{\circ}$\)

\(\displaystyle 257$^{\circ}$\)

\(\displaystyle 65.5$^{\circ}$\)

\(\displaystyle 103$^{\circ}$\)

Correct answer:

\(\displaystyle 128.5$^{\circ}$\)

Explanation:

The sum of the interior angles of any polygon can be found by applying the formula: 

\(\displaystyle 180 (n-2)\) degrees, where \(\displaystyle n\) is the number of sides in the polygon. 

By definition, a kite is a polygon with four total sides (quadrilateral). The sum of the interior angles of any quadrilateral must equal: \(\displaystyle 180(4-2)\) degrees \(\displaystyle =180(2)\) degrees \(\displaystyle =360\) degrees. Additionally, kites must have two sets of equivalent adjacent sides & one set of congruent opposite angles

The missing angle can be found by finding the sum of the non-congruent opposite angles. Then divide the difference between \(\displaystyle 360\) degrees and the non-congruent opposite angles sum by \(\displaystyle 2\):   

\(\displaystyle 44+59=103\)

\(\displaystyle 360-103=257\)

This means that \(\displaystyle 257\) is the sum of the remaining two angles, which must be opposite congruent angles. Therefore, the measurement for one of the angles is: 

\(\displaystyle \frac{257}{2}=128.5\) 

Example Question #242 : Geometry

A kite has one set of opposite interior angles where the two angles measure \(\displaystyle 58$^{\circ}$\) and \(\displaystyle 67$^{\circ}$\), respectively. Find the measurement of the sum of the two remaining interior angles.

Possible Answers:

\(\displaystyle 245$^{\circ}$\)

\(\displaystyle 135$^{\circ}$\)

\(\displaystyle 117.5$^{\circ}$\)

\(\displaystyle 235$^{\circ}$\)

\(\displaystyle 125$^{\circ}$\)

Correct answer:

\(\displaystyle 235$^{\circ}$\)

Explanation:

The sum of the interior angles of any polygon can be found by applying the formula: 

\(\displaystyle 180 (n-2)\) degrees, where \(\displaystyle n\) is the number of sides in the polygon. 

By definition, a kite is a polygon with four total sides (quadrilateral). The sum of the interior angles of any quadrilateral must equal: \(\displaystyle 180(4-2)\) degrees \(\displaystyle =180(2)\) degrees \(\displaystyle =360\) degrees. Additionally, kites must have two sets of equivalent adjacent sides & one set of congruent opposite angles

To find the sum of the remaining two angles, determine the difference between \(\displaystyle 360\) degrees and the sum of the non-congruent opposite angles.

The solution is:

\(\displaystyle 58+67=125\)

\(\displaystyle 360-125=235$^{\circ}$\)

This means that \(\displaystyle 235$^{\circ}$\) is the sum of the remaining two opposite angles.

Example Question #243 : Geometry

Q7

If the diagonals of the quadrilateral above were drawn in the figure, they would form four 90 degree angles at the center. In degrees, what is the value of \(\displaystyle x\)?

Possible Answers:

\(\displaystyle 57\)

\(\displaystyle 65\)

\(\displaystyle 73\)

\(\displaystyle 69\)

\(\displaystyle 61\)

Correct answer:

\(\displaystyle 61\)

Explanation:

A quadrilateral is considered a kite when one of the following is true:

(1) it has two disjoint pairs of sides are equal in length or

(2) one diagonal is the perpendicular bisector of the other diagonal. Given the information in the question, we know (2) is definitely true. 

To find \(\displaystyle x\) we must first find the values of all of the angles. 

The sum of angles within any quadrilateral is 360 degrees.

Therefore \(\displaystyle \angle D=\angle B\).

To find \(\displaystyle \angle A\):

 \(\displaystyle 360-115-115=130\)

\(\displaystyle 130=2(x+4)=2x+8\)

\(\displaystyle x=\frac{130-8}{2}=\frac{122}{2}=61\)

Example Question #11 : Quadrilaterals

In a particular kite, one angle that lies between congruent sides measures \(\displaystyle 50^{\circ}\), and one angle that lies between non-congruent sides measures \(\displaystyle 25^{\circ}\). What is the measure of the angle opposite the \(\displaystyle 50^{\circ}\) angle?

Possible Answers:

\(\displaystyle 260^{\circ}\)

\(\displaystyle 25^{\circ}\)

\(\displaystyle 50^{\circ}\)

\(\displaystyle 80^{\circ}\)

\(\displaystyle 225^{\circ}\)

Correct answer:

\(\displaystyle 260^{\circ}\)

Explanation:

One of the rules governing kites is that the angles which lie between non-congruent sides are congruent to each other. Thus, we know one of the missing angles is also \(\displaystyle 25^{\circ}\). Since all angles in a quadrilateral must sum to \(\displaystyle 360^{\circ}\), we know that the other missing angle is

\(\displaystyle \angle x = 360^{\circ} - (25^{\circ} + 25^{\circ} + 50^{\circ}) = 260^{\circ}\)

Example Question #1 : Quadrilaterals

Kite vt act

Using the kite shown above, find the length of the red (vertical) diagonal. 

Possible Answers:

\(\displaystyle 17\)

\(\displaystyle 17.5\)

\(\displaystyle 19\)

\(\displaystyle 15.5\)

\(\displaystyle 19.5\)

Correct answer:

\(\displaystyle 17\)

Explanation:

In order to solve this problem, first observe that the red diagonal line divides the kite into two triangles that each have side lengths of \(\displaystyle 15\) and \(\displaystyle 8.\) Notice, the hypotenuse of the interior triangle is the red diagonal. Therefore, use the Pythagorean theorem: \(\displaystyle a^2+b^2=c^2\), where \(\displaystyle c=\) the length of the red diagonal. 

The solution is: 

\(\displaystyle 8^2+15^2=c^2\)

\(\displaystyle 64+225=c^2\)

\(\displaystyle c^2=289\)

\(\displaystyle c=\sqrt{289}=\sqrt{17\times 17}=17\)

Example Question #4 : Kites

A kite has two perpendicular interior diagonals. One diagonal is twice the length of the other diagonal. The total area of the kite is \(\displaystyle 196\textup{ units}^{2}\). Find the length of each interior diagonal.

Possible Answers:

\(\displaystyle 7\textup{ and }14\)

\(\displaystyle 7^2\textup{ and }15\)

\(\displaystyle 15\textup{ and }45\)

\(\displaystyle 14\textup{ and }28\)

\(\displaystyle 15\textup{ and }30\)

Correct answer:

\(\displaystyle 14\textup{ and }28\)

Explanation:

To solve this problem, apply the formula for finding the area of a kite: 

\(\displaystyle Area=\frac{diagonalA\times diagonalB}{2}\)

However, in this problem the question only provides information regarding the exact area. The lengths of the diagonals are represented as a ratio, where 
\(\displaystyle diagonalA:diagonalB=1:2\)

Therefore, it is necessary to plug the provided information into the area formula. Diagonal \(\displaystyle A\) is represented by \(\displaystyle x\) and diagonal \(\displaystyle B=2\)\(\displaystyle x\).

The solution is:

\(\displaystyle 196=\frac{x\times 2x}{2}\)

\(\displaystyle 196\times2=x\times 2x\)

\(\displaystyle 392=2x^2\)

\(\displaystyle x^2=\frac{392}{2}=196\)

\(\displaystyle x=\sqrt{196}=14\)

Thus, if \(\displaystyle x=14\), then diagonal \(\displaystyle B\) must equal \(\displaystyle 2(14)=28\)


Example Question #1 : How To Find The Length Of The Diagonal Of A Kite

A kite has two perpendicular interior diagonals. One diagonal has a measurement of \(\displaystyle 8\) and the area of the kite is \(\displaystyle 60\textup{ units}^{2}\). Find the length of the other interior diagonal.

Possible Answers:

\(\displaystyle 30\)

\(\displaystyle 5.5\)

\(\displaystyle 7.5\)

\(\displaystyle \sqrt{15}\)

\(\displaystyle 15\)

Correct answer:

\(\displaystyle 15\)

Explanation:

This problem can be solved by applying the area formula: 



Since this question provides the area of the kite and length of one diagonal, plug that information into the equation to solve for the missing diagonal. 

Thus the solution is: 

\(\displaystyle 60=\frac{8\times diagonal B}{2}\)

\(\displaystyle 60\times2=8\times diagonalB\)

\(\displaystyle 120=8(diagonalB)\)

\(\displaystyle diagonal B=\frac{120}{8}=15\)

Example Question #6 : Kites

A kite has two perpendicular interior diagonals. One diagonal has a measurement of \(\displaystyle 18\) and the area of the kite is \(\displaystyle 45\textup{ units}^{2}\). Find the length of the other interior diagonal.

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 5\)

\(\displaystyle 9\)

\(\displaystyle 8.5\)

\(\displaystyle 5.5\)

Correct answer:

\(\displaystyle 5\)

Explanation:

This problem can be solved by applying the area formula: 



Since this question provides the area of the kite and length of one diagonal, plug that information into the equation to solve for the missing diagonal. 

Thus the solution is: 

\(\displaystyle 45=\frac{18\times diagonal B}{2}\)

\(\displaystyle 45\times2=18\times diagonalB\)

\(\displaystyle 90=18(diagonalB)\)

\(\displaystyle diagonal B=\frac{90}{18}=5\)

Example Question #7 : Kites

A kite has two perpendicular interior diagonals. One diagonal has a measurement of \(\displaystyle 250\) and the area of the kite is \(\displaystyle 6\textup{,}250\textup{ units}^{2}\). Find the sum of the two perpendicular interior diagonals.

Possible Answers:

\(\displaystyle 450\)

\(\displaystyle 200\)

\(\displaystyle 300\)

\(\displaystyle 50\)

\(\displaystyle 2\textup{,}000\)

Correct answer:

\(\displaystyle 300\)

Explanation:

First find the length of the missing diagonal before you can find the sum of the two perpendicular diagonals. 

To find the missing diagonal, apply the area formula: 




This question provides the area of the kite and length of one diagonal, plug that information into the equation to solve for the missing diagonal. 


\(\displaystyle 6,250=\frac{250\times diagonal B}{2}\)

\(\displaystyle 6250\times2=250\times diagonalB\)

\(\displaystyle 12,500=250(diagonalB)\)

\(\displaystyle diagonal B=\frac{12,500}{250}=50\)

Therefore, the sum of the two diagonals is: 

\(\displaystyle 250+50=300\)

Example Question #8 : Kites

A kite has two perpendicular interior diagonals. One diagonal has a measurement of \(\displaystyle 4\) and the area of the kite is \(\displaystyle 28\textup{ units}^{2}\). Find the sum of the two perpendicular interior diagonals.

Possible Answers:

\(\displaystyle 14\)

\(\displaystyle 18\)

\(\displaystyle 56\)

\(\displaystyle 28\)

\(\displaystyle 10\)

Correct answer:

\(\displaystyle 18\)

Explanation:

You must find the length of the missing diagonal before you can find the sum of the two perpendicular diagonals. 

To find the missing diagonal, apply the area formula: 




This question provides the area of the kite and length of one diagonal, plug that information into the equation to solve for the missing diagonal. 


\(\displaystyle 28=\frac{4\times diagonal B}{2}\)

\(\displaystyle 28\times2=4\times diagonalB\)

\(\displaystyle 56=4(diagonalB)\)

\(\displaystyle diagonal B=\frac{56}{4}=14\)

Therefore, the sum of the two diagonals is: 

\(\displaystyle 14+4=18\)

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