In the figure below, ABC and ADC are isosceles triangles. AB equal AC, AD equal DC and ABC equal 70°. Find ACD.
Given that ABC and ADC are isosceles triangles, we know that AB = AC and AD = DC.
Since ABC is an isosceles triangle, we can find the measure of angle BAC by using the fact that the sum of all interior angles in a triangle is 180°.
Therefore, angle BAC = 180° - 2(70°) = 40°.
Since AD = DC, we can conclude that angle ACD is also 40°, as it is the vertically opposite angle to angle BAC.
Therefore, ACD = 40°.