tolong nomer 21 ka :D

180° = (3x+15)° + (2x+10)°
180° = 3x+2x+15+10
180 = 5x + 25
180 - 25 = 5x
155 = 5x
x = 155 : 5
x = 31

Pelurus ∠KLN adalah ∠MLN
∠MLN = 2x+10
∠MLN = 2(31) + 10
∠MLN = 62 + 10
∠MLN = 72°