1. Measuring Angles

The measures of two angles of a triangle are given. Find the measure of the third angle. See Example 2. 37° , 52°

Length of a Shadow If a tree 20 ft tall casts a shadow 8 ft long, how long would the shadow of a 30-ft tree be at the same time and place?

The measures of two angles of a triangle are given. Find the measure of the third angle. See Example 2. 147° 12' , 30° 19'

The measures of two angles of a triangle are given. Find the measure of the third angle. See Example 2.

29.6° , 49.7°

The measures of two angles of a triangle are given. Find the measure of the third angle. See Example 2.

17° 41' 13" , 96° 12' 10"

Concept Check Classify each triangle as acute, right, or obtuse. Also classify each as equilateral, isosceles, or scalene. See the discussion following Example 2.

Concept Check Classify each triangle as acute, right, or obtuse. Also classify each as equilateral, isosceles, or scalene. See the discussion following Example 2.

Convert each radian measure to degrees. See Examples 2(a) and 2(b). ―7π/20

Convert each radian measure to degrees. See Examples 2(a) and 2(b). 11π/30

Concept Check Classify each triangle as acute, right, or obtuse. Also classify each as equilateral, isosceles, or scalene. See the discussion following Example 2.

Convert each radian measure to degrees. See Examples 2(a) and 2(b). 15π

Find the unknown side lengths in each pair of similar triangles. See Example 4.

Solve each problem. See Example 5. Height of a Lighthouse The Biloxi lighthouse in the figure casts a shadow 28 m long at 7 A.M. At the same time, the shadow of the lighthouse keeper, who is 1.75 m tall, is 3.5 m long. How tall is the lighthouse?

Solve each problem. See Example 5. Height of a Building A house is 15 ft tall. Its shadow is 40 ft long at the same time that the shadow of a nearby building is 300 ft long. Find the height of the building.

Solve each problem. See Example 5. Height of a Carving of Lincoln Assume that Lincoln was 6 1/3 ft tall and his head was 3/4 ft long. Knowing that the carved head of Lincoln at Mt. Rushmore is 60 ft tall, find how tall his entire body would be if it were carved into the mountain.