Advanced Geometry : How to find the length of the diagonal of a kite

Study concepts, example questions & explanations for Advanced Geometry

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Example Questions

Example Question #21 : How To Find The Length Of The Diagonal Of A Kite

If the area of the kite is \displaystyle 100 square units, and the difference between the lengths of the diagonals is \displaystyle 10 units, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 25

\displaystyle 10

\displaystyle 15

\displaystyle 20

Correct answer:

\displaystyle 10

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+10.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 100=\frac{x(x+10)}{2}

\displaystyle x^2+10x=200

\displaystyle x^2+10x-200=0

\displaystyle (x+20)(x-10)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=10.

The length of the shorter diagonal is \displaystyle 10 units long.

Example Question #311 : Advanced Geometry

If the area a kite is \displaystyle 88 square units, and the length of one diagonal is \displaystyle 5 units longer than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 11

\displaystyle 13

\displaystyle 7

\displaystyle 9

Correct answer:

\displaystyle 11

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+5.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 88=\frac{x(x+5)}{2}

\displaystyle x^2+5x=176

\displaystyle x^2+5x-176=0

\displaystyle (x+16)(x-11)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=11.

The length of the shorter diagonal is \displaystyle 11 units long.

Example Question #21 : Kites

If the area of a kite is \displaystyle 64 square units, and the length of one diagonal is \displaystyle 8 units longer than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 20

\displaystyle 12

\displaystyle 16

\displaystyle 8

Correct answer:

\displaystyle 8

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+8.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 64=\frac{x(x+8)}{2}

\displaystyle x^2+8x=128

\displaystyle x^2+8x-128=0

\displaystyle (x+16)(x-8)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=8.

The length of the shorter diagonal is \displaystyle 8 units long.

Example Question #21 : Quadrilaterals

If the area of a kite is \displaystyle 114 square units, and one diagonal is \displaystyle 7 units longer than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 12

\displaystyle 15

\displaystyle 17

\displaystyle 19

Correct answer:

\displaystyle 12

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+7.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 114=\frac{x(x+7)}{2}

\displaystyle x^2+7x=228

\displaystyle x^2+7x-228=0

\displaystyle (x+19)(x-12)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=12.

The length of the shorter diagonal is \displaystyle 12 units long.

Example Question #21 : How To Find The Length Of The Diagonal Of A Kite

If the area of a kite is \displaystyle 104 square units, and the length of one diagonal is \displaystyle 3 less than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 18

\displaystyle 15

\displaystyle 13

\displaystyle 12

Correct answer:

\displaystyle 13

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+3.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 104=\frac{x(x+3)}{2}

\displaystyle x^2+3x=208

\displaystyle x^2+3x-208=0

\displaystyle (x+16)(x-13)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=13.

The length of the shorter diagonal is \displaystyle 13 units long.

Example Question #21 : Kites

If the area of a kite is \displaystyle 18 square units, and the length of one diagonal is \displaystyle 5 units longer than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 7

\displaystyle 9

\displaystyle 5

\displaystyle 4

Correct answer:

\displaystyle 4

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+5.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 18=\frac{x(x+5)}{2}

\displaystyle x^2+5x=36

\displaystyle x^2+5x-36=0

\displaystyle (x+9)(x-4)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=4.

The length of the shorter diagonal is \displaystyle 4 units long.

Example Question #27 : How To Find The Length Of The Diagonal Of A Kite

If the area of a kite is \displaystyle 20 square units, and one diagonal is \displaystyle 3 units longer than the other, what is the length of the longer diagonal?

Possible Answers:

\displaystyle 7

\displaystyle 12

\displaystyle 8

\displaystyle 9

Correct answer:

\displaystyle 8

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+3.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 20=\frac{x(x+3)}{2}

\displaystyle x^2+3x=40

\displaystyle x^2+3x-40=0

\displaystyle (x+8)(x-5)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=5.

To find the longer diagonal, add \displaystyle 3.

The length of the longer diagonal is \displaystyle 8 units long.

Example Question #22 : How To Find The Length Of The Diagonal Of A Kite

If the area of a kite is \displaystyle 1680 square units, and the length of one diagonal is \displaystyle 4 units shorter than the other, what is the length of the shorter diagonal?

Possible Answers:

\displaystyle 58

\displaystyle 56

\displaystyle 52

\displaystyle 50

Correct answer:

\displaystyle 56

Explanation:

Let \displaystyle x be the length of the shorter diagonal. Then the length of the longer diagonal can be represented by \displaystyle x+4.

Recall how to find the area of a kite:

\displaystyle \text{Area}=\frac{(\text{Diagonal 1})(\text{Diagonal 2})}{2}

Plug in the given area and solve for \displaystyle x.

\displaystyle 1680=\frac{x(x+4)}{2}

\displaystyle x^2+4x=3360

\displaystyle x^2+4x-3360=0

\displaystyle (x+60)(x-56)=0

Since we are dealing with geometric shapes, the answer must be a positive value. Thus, \displaystyle x=56.

The length of the shorter diagonal is \displaystyle 56 units long.

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