nomor 22&23 ket no 22: ps= 20cm sr= 30cm su= 21cm

22.
Segitiga PST sebangun dengan segitiga RSU
maka :
PS.......ST
----- = ------
RS........SU

20........ST
------ = ------
30..........21

ST × 30 = 20 × 21
30ST = 420
ST = 420/30
ST = 14
Jadi panjang ST adalah 14 cm (b)

23.
SEGITIGA ABC
m < A = (4x + 10)°
m < B = (5x - 30)°
m < C = (6x - 40)°

< A + < B + < C = 180°
(4x + 10 + 5x - 30 + 6x - 40)° = 180°
15x° - 60° = 180°
15x° = 180° + 60°
15x° = 240°
x = 240°/15°
x = 16

< C = (6x - 40)°
< C = (6 × 16 - 40)°
< C = (96 - 40)°
< C = 56°
jadi besar < C adalah 56° (d)