tolong jawab nomor 7-13 pakai cara ya

7). 2×{(3x+45)+(4x-5)} = 360°
2×(7x+40) = 360
14x+80 = 360
14x = 280
x = 20
sudut PSR = 4x-5 = 4(20)-5 = 75

8). sudut PRT = sudut STQ = 70°
sudut TSQ = 80
sudut SQT = 180°-80°-70° = 30°

9). 90°/360° = 1/4
jadi, sudut 90° = sudut 1/4 putaran

10). 1/3 × 360° = 120°
sudut 120° lebih dari 90°, maka sudut 120° termasuk sudut tumpul

11). A:B = 1:3
1x+3x= 180°
4x = 180°
x = 45°
sudut B = 3x = 3(45) = 135°

12). 49°35'38"
........18°40'43"
-------------------- +
........67°75'81"
67°+1°+15'+1'+21"
68°+16'+21"

13). 3x+2x = 90°
5x = 90
x = 18

sudut BAD = 2x = 2(18) = 36°