Question

Quadrilateral ABCD is a kite. If AD=AB, find AD

A. 5/3
B. 7
C. 5/7
D. 22

Answer 1

AD = AB

AD = 2r+8
AB = 5r-13

we need to find the value of r to find the total length

so 2r+8 = 5r-13
subtract 2r from each side:
8 = 3r -13
add 13 to each side:
21 = 3r
divide both sides by 3
r = 21 / 3 = 7
r=7
now we know r, so replace r with 7 in the equation for AD

AD = 2r+8 = 2(7) +8 = 14 +8 = 22

the answer is D. 22