mohon bantuan nya jawab kan no 2 yg ada di foto tolong bantuan nya

a. AB = ✓OB^2-OA^2
AB = ✓20^2-12^2
AB = ✓400-144
AB = ✓256
AB = 16 cm

b. L.layang OABC = 2 x OAB
= 2 x ( 1/2 x OA x AB )
= 2 x ( 1/2 x 12 x 16 )
= 2 x 96
= 192 cm^2