Find the area of an equilateral triangle of perimeter 30 cm

≈ 43.3 cm²

Step-by-step explanation:

The area (A) of an equilateral triangle is calculated as

A = (  s is the side length )

The 3 sides of an equilateral triangle are congruent, thus

s = 30 ÷ 3 = 10 cm

A = = = 25 ≈ 43.3 cm²

43.30cm²

Step-by-step explanation:

Use Herons formula

S = (a+b+c)÷2

Where a, b, c is the sides of the triangle

If perimeter is 30cm

Since it's an equilateral triangle, all sides are equal.

Then

Perimeter = 3a = 30

a = 30/3 = 10cm

b = 10cm , c = 10cm

Therefore ,s=  (10+10+10)÷2 = 30÷2 = 15cm

From Herons formula

Area = square root of s(s-a)(s-b) (s - c)

Area = sq rt 15(15 - 10)(15 - 10)(15 - 10)

Area = sq rt 15.× 5 × 5 ×5

Area = sq rt 1875

Area = 43.30cm²

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