What is the area of an equilateral triangle of perimeter 30 cm?

Step 1: Note down the given values and recall the perimeter of the equilateral triangle.
NOTE: Perimeter of equilateral = 3* a
Where a is the side of the equilateral
Step 2: Find the side of the equilateral triangle by using the perimeter formula
NOTE: Perimeter of equilateral = 3* a
a = \frac{Perimeter of equilateral}{3}
EXAMPLE: Side a = \frac{30}{3}
Side a = 10 cm
Step 3: Set up a area formula of an equilateral triangle.
NOTE: Equilateral triangle all sides are equal.
Area of equilateral triangle = \frac{\sqrt{3}}{4} a^2
Step 4: Plug in the side (a) value in the area of the equilateral triangle formula
EXAMPLE: Side a = 10 cm
= \frac{\sqrt{3}}{4} a^2
= \frac{\sqrt{3}}{4} (10)^2
Step 5: Do Some calculations for the required area.
EXAMPLE = \frac{\sqrt{3}}{4} (100)
= \sqrt{3}* 25
= 25 \sqrt{3}