Answer:
Tổng 3 góc trong 1 tam giác là 180 độ
Vậy góc B = 180 - A - C = 180 - 90 - 50 = 40 độ
To find arc WY:
360 - 156 - 86
arc WY = 118
To find angle WXY
118 / 2 = 59 degrees
You could understand the ration as parts: the total number of parts was 3+7=10.
So girls were 3/10 parts and boys 7/10 parts. The difference was 7-3=4 parts. this difference is equal to 360, so each part is 90 (4*90 =360).
so girls are "3 parts" and each part is 90, then the number of girls is 3*90=270.
The answer is (4x11)-7 i believe
