CPM Homework Banner

Home > GC > Chapter 11 > Lesson 11.1.5 > Problem 11-66


Hokiri’s ladder has two legs that are each feet long. When the ladder is opened safely and locked for use, the legs are feet apart on the ground. What is the angle that is formed at the top of the ladder where the legs meet?  

Create a diagram of the ladder with a perpendicular bisector from the top () to the base ().

Next, use the right triangle and a calculator to find the angle whose sine is equal to .


Since  is half of the desired angle, double to get .

Triangle, with vertices labeled, bottom left, A, bottom right, B, top, C. A dashed line segment from, C, perpendicular to base, at point labeled, D. Left and right sides, of triangle, A, B, C, each labeled, 8. Segments, A, D, &, D, B, each labeled 2.