Question

In the figure at right, it is given than BDC is straight, BD = DA, and AB = AC = DC. Find the size of angle C

Answer 1

do you know what an isosceles triangle is and what its properties are?

Answer 2

Yeah. I figured angles B and DAB must be equal, angles CDA and CAD must be equal, and angles B and C must be equal

Answer 3

you are almost there - now assign a symbol to angle ABD - lets call it x, and fill-in all the other angles you know using this symbol, e.g. from what you have already said we get:


now find y in terms of x and then use the property of the sum of the angles in a triangle to solve for x.