Question

Need help on geometry please

Answer 1

What is the area of an equilateral triangle  with a side measuring 12 inches?

In getting for the area of an equilateral triangle, following the formula for a triangle given the two sides with an included angle:
A= 1/2 (absin(tetha))
Since, it is an equilateral triangle, it also has same angles
180/3 = 60 degrees, each angle is equivalent to 60 degrees

Since the sides are all equal, thus a=b

Substitute in the formula;
A=1/2 (a^2)(sin 60)
A= 1/2 (a^2) (sqrt 3 / 2)

Thus; the formula is now:
A= sqrt 3/4 (a^2) 
where a is the side
A= sqrt3 / 4 (12)^2
A= 62.35 square inches 

Answer 2

The answer is 62.354 square inches .