Answer:
The unknown side is 140
Step-by-step explanation:
Let the unknown side be x
Using ratios
90 90+36
------ = -----------
x x+56
90 126
Using cross products
90(x+56) = 126x
Distribute
90x+5040 = 126x
Subtract 90x
5040 = 36x
Divide by 36
140 =x
