4. A 20.0m tall tree makes an angle of 12o with the vertical. To prevent the tree from falling over any
more a 35.0m rope is attached to the top of the tree and is pegged into the ground some distance
away. Find the angle the rope makes with the ground.
5. An engineer wants to build a bridge over a river from point B to point A. The distance from B to a
point C is 520.0m. A transit is used and
B is found to be 78o
.
C is found to be 54o
. How long will be the bridge be ?
Draw a diagram. Let
T = top of tree
B = bottom of tree
R = anchor point for rope
Now use the law of sines to find angle R:
sinR/20 = sin102°/35