Question

ABCD is a square. Triangle DEF is equilateral. Triangle ADE is isosceles with AD = AE. CDF is a straight line. Showing all your steps, calculate the size of angle AEF​

Answer 1

90°

Explanation:

the sum of all angles in a triangle is always 180°.

in an equilateral triangle also all 3 angles are equal and therefore 180/3 = 60°.

angle EDF = 60°.

angle DEF = 60°

all angles in a square are 90°.

so, angle ADC = 90°.

and therefore, ADF = 90°.

the angle ADE is then 90-60 = 30°.

the triangle ADE is isoceles (both legs are equal, and both angles of the legs with the baseline are equal).

so, the angle AED = angle ADE = 30°

the angle AEF is then angles AED + DEF = 30 + 60 = 90°