tolong dibantu yaa, pakai cara ny.. trmksih :)

Materi : segitiga dan segiempat
Kelas : 7 SMP

1.
a)
∠P + ∠Q = 180
x + 31 + 2x + 10 = 180
x + 2x = 180 - 10 - 31
3x = 139
x = 139/3
x = 46,33

b)
∠Q = 2x + 10
∠Q = 2(46,33) + 10
∠Q = 92,66 + 10
∠Q = 102,66°

2.
a)
AB = CD
5x - 18 = 3x + 10
5x - 3x = 10 + 18
2x = 28
x = 28/2
x = 14

b)
AB = 5x - 18
AB = 5(14) - 18
AB = 70 - 18
AB = 52 cm

c)
∠A = 7 / (7+5) × 180
= 7/12 × 180
= 105°