Acarpenter is making a wooden window frame that has a width of 1 inch.

a window with a one-inch frame is shown. the frame is comprised of a rectangle and a semicircle. the rectangle has side lengths of 12 inches and 48 inches. the semicircle has a radius of 6 inches. the frame is 1-inch wider than the window.

how much wood does the carpenter need to build the frame?

1. 180°. the sum of the interior angles of a triangle is 180°, for the equilateral triangle that it has three equals side is 60°+60°+60°=180°.

2. 60°. each interior angle of a equilateral triangle is 60°

3. 120°. the measure of ∠m is 120°, the sum of the angles ∠m and ∠n is equal to 180°. so, in order to find the measure of ∠m, we have ∠m+∠n=180° > ∠m=180°-∠n > ∠m=180°-60°=120°.

4. 360°. the sum of the exterior angles of an equilateral triangle is ∠m+∠r+∠x=120°+120°+120°=360°. the exterior angles of any triangle always add 360°.