no 13 pake caranya ya.... kak

L layang-layang = 1/2 x d1 x d2
= 1/2 x (6+15) x (8+8)
= 1/2 x 21 x 16
= 21 x 8
= 168 dm persegi

L 1/2 lingkaran = 1/2 π r r
= 1/2 x 3,14 x 10 x 10
= 1/2 x 314
= 157 dm persegi

L gabungan = L layang-layang+L 1/2 lingkaran
= 168+157
= 325 dm persegi

*semoga membantu. sukses selalu ^_^

L layang2 = 1/2 x d1 x d2
= 1/2 x 21 x 16
= 21 x 8 = 168 dm²
1/4 + 1/4 = 1/2 L lingkaran
= 1/2 x 3,14 x 10x 10
= 1,57 x 10 x 10
= 157 dm²

L layang2 + L lingkaran
= 168 + 157
= 325 dm²

maaf klo slh