Exercise 4: Work out the orange angle.

The points A, F and E are aligned.

Complete the following proof :

As the triangle AFI is right angled and

at , each of its acute angles measures  .

Thus the angle AF measures 45°.

In the triangle HIF, the sum of the angles equals .

Thus angle IFH = - (113 + ) =

As the triangle HFG is , the angle HFG measures .

As the points A, F and E are aligned, the angle AFE measures .

Thus angle GFE = 180 - (45 + + 60) = .

The orange angle measures 40°.