tolong jawab no 3 dan 4

3.
misal P2 dan P3 = x
P1 + P2 + P3 = 180
128 + x + x = 180
128 + 2x = 180
2x = 52
x = 26°

maka nilai P2 dan P3 = 26°

P2 + P3 = R1 = R2
2x = R1 = R2
52 = R1 = R2
R1 + R2 + R3 = 180
2x + 2x + R3 = 180
4x + R3 = 180
4(26) + R3 = 180
104 + R3 = 180
R3 = 76°

P2 + R2 + Q = 180
26 + 52 + Q = 180
78 + Q = 180
Q = 102°

4.
CBD + ABC = 180
120 + ABC = 180
ABC = 60°

ABC = ACB = 60°
ABC + ACB + BAC = 180
60 + 60 + BAC = 180
120 + BAC = 180
BAC = 60