Answer:
18.7 feet.
Step-by-step explanation:
Please consider the complete question.
A guy wire for a tree is 20 ft long, making a 21 degree angle with the ground. How far is the base of the tree from a stake anchoring the wire?
First of all, we will draw a relevant diagram to represent the given scenario. Our diagram would be a right triangle with hypotenuse of 20 ft and x as adjacent side to angle 21 degrees as represented in the attachment.
We know that cosine relates opposite side of right triangle with its hypotenuse.






Upon rounding to nearest tenth, we will get:

Therefore, the stake is anchoring approximately 18.7 feet away from the base of the tree.