bantu jawab no. 3 dan 4

3.
A.
(I)
180-(30+90)
180-120=60
(II)
180-(45+90)
189-135=45
(III)
180-(35+90)
180-125=55
B.segitiga siku²
C.
(I)
30+60=90
(II)
45+45=90
(III)
35+55=90
4.
(I)
180=35+3a+2a
180=35+5a
180-35=5a
145/5=a
29=a
(II)
180=2b+2b+2b
180=6b
180/6=b
30=b
(III)
180=3c+c+c
180=5c
180/5=c
36=c