Printable

2009 AMC 10B Problem 24

Include the solution Back to the problem

2009 AMC 10B Problem 24AMC 10 Step by Step

Name: Date: September 13, 2026

Angles & Polygons · difficulty 4 of 5 · about 5 min · position P21-25

The keystone arch is an ancient architectural feature. It is composed of congruent isosceles trapezoids fitted together along the non-parallel sides, as shown. The bottom sides of the two end trapezoids are horizontal. In an arch made with $9$ trapezoids, let $x$ be the angle measure in degrees of the larger interior angle of the trapezoid. What is $x$ ?

A)
$100$
B)
$102$
C)
$104$
D)
$106$
E)
$108$

2009 AMC 10B Problem 24

Working