Answer:
√41
Explanation:
Considering the largest triangle,
The unknown side = √[(52)^2 + (40)^2]
= √400
= 20
Considering the second largest,
The unknown side = √[(20)^2 + (12)^2]
= √256
= 16
Considering the the smaller one,
Using pythagoras theorem
Unknown side = 12
The base of the smallest triangle is 16 - 12 = 4
hence x = √[(4)^2 + (5)^2]
= √41