ACT Math : Quadrilaterals

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #1 : How To Find An Angle In A Parallelogram

Parallelogram_2

In parallelogram . What is ?

Possible Answers:

Correct answer:

Explanation:

In parallelogram  and  are opposite angles. In a parallelogram, opposite angles are congruent. This means these two angles are equal.

Example Question #10 : How To Find An Angle In A Parallelogram

Parallelogram_2

In parallelogram , what is the sum of  and ?

Possible Answers:

Correct answer:

Explanation:

In a parallelogram, consecutive angles are supplementary.   and  are consecutive, so their sum is .

Example Question #11 : How To Find An Angle In A Parallelogram

Parallelogram_6

 is a parallelogram. Find .

Possible Answers:

Correct answer:

Explanation:

In a parallelogram, consecutive angles are supplementary and opposite angles are congruent. Using these properties, we can write a system of equations. Because we have three variables, we will need three equations.

1. 

2. 

3. 

 

Start with equation 1.

 

Now simplify equation 2.

 

Finally, simplify equation 3.

 

Note that we can plug this simplified equation 3 directly into the simplified equation 2 to solve for .

Now that we have , we can solve for  using equation 1.

With , we can solve for  using equation 3.

Now that we have  and , we can solve for .

 

Example Question #12 : How To Find An Angle In A Parallelogram

Parallelogram_8

 is a parallelogram. Find .

Possible Answers:

Correct answer:

Explanation:

In a parallelogram, consecutive angles are supplementary and opposite angles are congruent.

 

Example Question #1 : Parallelograms

In the parallellogram, what is the value of ?

Screen_shot_2013-07-15_at_9.42.14_pm

Possible Answers:

Correct answer:

Explanation:

Opposite angles are equal, and adjacent angles must sum to 180.

Therefore, we can set up an equation to solve for z:

(z – 15) + 2z = 180

3z - 15 = 180

3z = 195

z = 65

Now solve for x:

2= x = 130°

Example Question #1 : How To Find The Length Of The Side Of A Parallelogram

Parallelogram_2

In parallelogram  and . Find .

Possible Answers:

There is insufficient information to solve the problem.

Correct answer:

Explanation:

In a parallelogram, opposite sides are congruent. Thus,

Example Question #2 : How To Find The Length Of The Side Of A Parallelogram

Parallelogram_2

In parallelogram  and . Find .

Possible Answers:

There is insufficient information to solve the problem.

Correct answer:

Explanation:

In a parallelogram, opposite sides are congruent.

Example Question #3 : How To Find The Length Of The Side Of A Parallelogram

Parallelogram_9

Parallelogram  has an area of . If , find .

Possible Answers:

There is insufficient information to solve the problem.

Correct answer:

Explanation:

The area of a parallelogram is given by:

In this problem, the height is given as  and the area is . Both  and  are bases.

Example Question #81 : Quadrilaterals

Parallelogram_10

 is a parallelogram. Find .

Possible Answers:

There is insufficient information to solve the problem.

Correct answer:

Explanation:

 is the hypotenuse of the right triangle formed when we draw the height of the parallelogram. Because it is a right triangle, we can use SOH CAH TOA to solve for . With respect to , we know the opposite side of the triangle and we are looking for the hypotenuse. Thus, we can use the sine function to solve for .

Example Question #5 : How To Find The Length Of The Side Of A Parallelogram

Find the length of the base of a parallelogram with a height of  and an area of .

Possible Answers:

Correct answer:

Explanation:

The formula for the area of a parallelogram is:

By plugging in the given values, we get:

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