Question

The area of a field shaped like a right triangle is 750yd^2.One leg of the field is fenced with wood costing $5/yd. the remainder of the perimeter of the field is fenced with steel costing $10/yd. the perimeter of the field is 150yd. The total cost of the fencing is $1200.
A- What is the length of the leg fenced with wood?
B- What is the length of the leg fenced with steel?

Answer 1

Assume that
 a and b = the two legs of the right triangle. 
 c =  the hypotenuse.

The area of the right triangle is 750 yd², therefore
(1/2)*a*b = 750
ab = 1500               (1)

The perimeter is 150yd, therefore
a + b + c = 150         (2)

Let the side fenced with wood be a, at $5/yd.  Sides b and c are fenced with steel at $10/y. The total cost is $1200, therefore
 5a + 10b + 10c = 1200            
or
a + 2b + 2c = 240         (3)

From (2), obtain 
c = 150 - a - b              (4)

Substitute (4) into (3)
a + 2b + 2(150 - a - b) = 240
-a + 300 = 240
a = 60

From (1), obtain
60b = 1500
b = 25

From (4), obtain
c = 150 - 60 - 25 = 65

Answer:
A. The length of the leg fenced with wood is 60 yd.
B.  The length of the leg fenced with steel is 25 yd.