Question:
The perimeter of an equilateral triangle is 60 m. The area is
(a)10√3 m2
(b) 15√3 m2
(c)20√3 m2
(d) 100√3 m2
Thinking Process
(i) First, determine the side of an equilateral by usingformula, perimeter=3x.
(ii) Further, substitute the value of x in the formula, area of an equilateral triangle = √3/4 (a)2 and simplify it.
Solution:
(d) Let each side of an equilateral be x.
Then, perimeter of an equilateral triangle = 60 m
x + x + x = 60 => 3x = 60 => x = 60/3 = 20 m
Area of an equilateral triangle = √3/4 (Side)2 = (√3/4) x 20 x 20 = 100 √3 m2
Thus, the area of triangle is 100√3 m2.