39. Marsha is using an 8-ft ladder to pick apples from a tree. The bottom of the ladder makes an angle of $70^{\circ}$ with the ground. How high up the tree does the ladder reach, to the nearest tenth of a foot?
3
Answer
\(\boxed{7.5}\) feet is the height the ladder reaches up the tree, to the nearest tenth of a foot.
Step 1 ：Given an 8-ft ladder and an angle of $70^\circ$ with the ground, we need to find the height the ladder reaches up the tree.
Step 2 ：Use the sine function to find the height: height = ladder_length * sin(angle)
Step 3 ：Substitute the given values: height = 8 * sin(70)
Step 4 ：Calculate the height: height = 7.5175409662872665
Step 5 ：Round the height to the nearest tenth of a foot: height = 7.5
Step 6 ：\(\boxed{7.5}\) feet is the height the ladder reaches up the tree, to the nearest tenth of a foot.
