Answer :
Given:
for example, a and b are the leg of the triangle
a = b - 4
h = 20 ft
Solution:
Use pythagoras theorem to find the solution
a² + b² = h²
(b - 4)² + b² = 20²
b² - 8b + 16 + b² = 400
2b² - 8b +16 - 400 = 0
2b² - 8b - 384 = 0
-------------------------- (each side divided by 2)
b² - 4b - 192 = 0
(b - 16)(b + 12) = 0
b = 16 or b = -12
The length of side can't be negative, so the value of b is 16
Subtitute the value of b to the equation to find a
a = b - 4
a = 16 - 4
a = 12
The lengths of the two legs are 12 ft and 16 ft
for example, a and b are the leg of the triangle
a = b - 4
h = 20 ft
Solution:
Use pythagoras theorem to find the solution
a² + b² = h²
(b - 4)² + b² = 20²
b² - 8b + 16 + b² = 400
2b² - 8b +16 - 400 = 0
2b² - 8b - 384 = 0
-------------------------- (each side divided by 2)
b² - 4b - 192 = 0
(b - 16)(b + 12) = 0
b = 16 or b = -12
The length of side can't be negative, so the value of b is 16
Subtitute the value of b to the equation to find a
a = b - 4
a = 16 - 4
a = 12
The lengths of the two legs are 12 ft and 16 ft