Doldrums are caused by solar radiation from the sun. Because of this the sunlight beams warms the air and causes it to rise straight up instead of side to side (horizontally).
Angles in a triangle add up to 180 degrees.
180 - 125 = 55
Add the ratios 4+7 = 11
Divide the left over angels by the ratio: 55/11 = 5
Now multiply 5 by each side of the ratio:
4:7
4*5 = 20
7*5 = 35
So the 2 angles are 20 and 35 degrees.
To check, you can add up all the angels : 20 + 35 + 125 = 180
So we know 20 and 35 is correct because it adds up to 180 degrees :)
it should be letter c I hope this help
The wheel is just an estimate
Also it shows stuff that should happen but in reality it's just a prediction