Let △ABC and △CDE be equilateral triangles of the same size, and angle BCD = 80∘ between them. Find the measure of angle BAD in degrees.

Guest Dec 28, 2019

#1**+1 **

Equilateral triangles, so both angles near C are 60 degrees

so angle ACD = 80 + 60 = 140 degrees

AC and CD are equal in length, so triangle ACD is isoceles

unlabelled angle A and D are equal 180 - 140 = 40 dgrees so A and D are 20 degrees each

BAD = 60 - 20 = 40 degrees

ElectricPavlov Dec 28, 2019

#1**+1 **

Best Answer

Equilateral triangles, so both angles near C are 60 degrees

so angle ACD = 80 + 60 = 140 degrees

AC and CD are equal in length, so triangle ACD is isoceles

unlabelled angle A and D are equal 180 - 140 = 40 dgrees so A and D are 20 degrees each

BAD = 60 - 20 = 40 degrees

ElectricPavlov Dec 28, 2019