Online Course Discussion Forum

Math II-A Geometry 1.28

Picture of Claire Zheng
Math II-A Geometry 1.28
by Claire Zheng - Wednesday, November 25, 2020, 9:05 PM
Let ABC be a triangle with AB = AC and ∠BAC = 20°, and let P be a point on side AB such that AP = BC. Find ∠ACP. I know that ABC is a isosceles triangle with B and C as 80° each. Since two segments are equal to each other, there is probably something involving either congruent or similar triangles, or both.  Can I get a hint for how to solve this? Thank you.
Picture of Dr. Kevin Wang
Re: Math II-A Geometry 1.28
by Dr. Kevin Wang - Wednesday, November 25, 2020, 11:51 PM

You are on the right track.  Since $AP=BC$, can you make a new triangle with base $AP$ and congruent to $\triangle ABC$?