Tolong jawab semuanya ya.... Kakak kakak...

2.
AD^2 = 10^2-8^2

AD = 6 cm

CB^2 = 8^2 + 15^2

CB = 17

K = CB + AB + AC
K = 17 + 15 + 8 = 40 cm
3.

K = AC+AB+BC

AC = CB = 15 cm
CD = 12 cm

AB = 2×AD

AD^2 = 15^2 - 12^2

AD = 9 cm

AB = 18 cm

K = 15 + 15 + 18 = 48 cm