Let m∠CLN = x. Then m∠ALM = 3x, and m∠A = 90°-x, m∠C = 90°-3x.
The sum of angles of ∆ABC is 180°, so we have
... 180° = 40° + m∠A + m∠C
Using the above expressions for m∠A and m∠C, we can write ...
... 180° = 40° + (90° -x) + (90° -3x)
... 4x = 40° . . . . . . . . . add 4x-180°
... x = 10°
From which we conclude ...
... m∠C = 90°-3x = 90° - 3·10° = 60°
The ratio of CN to CL is
... CN/CL = cos(∠C) = cos(60°)
... CN/CL = 1/2
so ...
... CN = (1/2)CL
We have been given that a rectangular yard is fenced in using 319 feet of custom fence Your friends really like the fence and decide to fence in their yard using the same fence. Their yard is similar but has a scale factor of 8/5 times the size of yours.
We are asked to find the length of fence that your friends should purchase.
Since the size of your friend's yard is times your yard, so your friend should purchase
times the 319 feet.
Upon rounding our answer to nearest foot, we will get:
Therefore, your friends should purchase 510 feet of fence and option C is the correct choice.