tolong bantu jawab yang nomor 1

Gambar 1. 2/5 x90 = 36
Gambar 2. Ga tau

(+) 3a+2a =90
5a =90
a=90:5
a= 18

(+) 5a+15+a+29+46 = 180
6a+90 = 180
6a = 180-90
6a = 90
a = 90:6
a = 15