Tentukan luas △ABC jika diketahui: a. Panjang sisi a = 5 cm besar < A = 30° dan < C = 45° b. Panjang sisi a = 6cm besar < A = 60° dan < C = 45°

a.
<B = 180 - 30 -45 = 105°

a/sin A = b/ sin B
5 sin 105/sin 30 = b
b = 9,66 cm

luas
= 1/2 a b sin C
= 1/2 * 5 * 9,66 sin45
= 17cm²

c.
<B = 180 - 45 - 60 = 75°

a/sin A = b /sin B
6/sin 60 = b/sin 75
b = 6 sin 75 / sin 60
b = 6,69 cm

luas
= 1/2 a b sin C
= 1/2 * 6 * 6,69 sin 45
= 14,19cm²