tolong bantuannya!!! 30-34,please!!!

30)
BD² = 8² + 6²
BD² = 64+36
BD = √100
BD = 10
<==>
AD² = DE × DB
6² = DE × 10
36 = DE × 10
DE = 3,6

31)
Keliling = 3,14 × diameter
37,68 = 3,14 × d
d = 37,68 / 3,14
d = 12 <=> d = 2 r
2r = 12
r = 6

32)