please show all formulas ABCD is a parallelogram What is the

ABCD is a parallelogram. What is the length of diagonal AC? [A] 336 [B] 58 [C] 116 [D] 640

Solution

In Parallelogram

AF = FC

=> 3n - 6 = 5n - 122

on solving this , we get n = 58

Now the lenght of the diagonal AC will be the sum of AF and FC

=> 3n - 6 + 5n - 122

=> 8n - 128

=> 8 * 58 - 128

=> 336 is the lenght of diagonal.

Option A is the correct answer.