Question

The length of the base of an isosceles triangle is 12 inches. Each base angle measures 50°. Which is a feasible plan

to find the length of each congruent side of the triangle? Justify each step.

Answer 1

Draw in a perpendicular bisector (height) Use cosine to find the missing side.

Explanation:

Isosceles means that two sides are the same (and the two base angles also) Making the height will bisect (cut in half) the given base. So you will have a right triangle with a known side and angle. Then you can use trigonometry to solve. See image.