Question

A sail is in the form of a right triangle. The angle at its lower edge is 57o. Which is the size of the angle formed at the top of the sail?

Answer 1

what do the angles of a triangle add up to?

Answer 2

once you have that.....you know that a right angle = 90 degrees...and you have another angle of 57 degrees

so when you say what the angles add up to in a triangle......you would merely subtract the sum of 90 and 57 ..from it