Answer:
5.5² - A² = 3.5²
30.25 - A² = 12.25
A² = 18
A = 3√2 = 4.24 meters (H)
8.8² - B² = 3.5²
77.44 - B² = 12.25
B² = 65.19
B = 8.07 meters (C)
9.3² - C² = 3.5²
86.49 - C² = 12.25
C² = 74.24
C = 8.62 meters (F)
7.9² - D² = 3.5²
62.41 - D² = 12.25
D² = 50.16
D = 7.08 meters (D)