Value of h
please help me, I don't understand

Answer: h = 14.1 ft
Step-by-step explanation:
The given triangle is an isosceles right angle triangle because the two sides or legs of the triangle are equal. To determine h, we would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side²
Hypotenuse = 20ft
opposite side = adjacent side = h feet
Therefore
20² = h² + h²
400 = 2h²
h² = 400/2 = 200
Taking square root of both sides, it becomes
h = √200
h = 14.1 ft