Question

If the perimeter of the triangle is 40 cm, find the area of the triangle.

The area of the triangle is, ? cm2.

Answer 1

60cm²

Explanation:

To find :-

• The Area of the triangle .

We know that Perimeter is the sum of sides of a triangle. Here the perimeter is 40cm .

→ 2x - 4 +5x - 13 + x + 9 = 40cm .

→ 8x - 8 = 40cm

→ 8x = 40+8 cm

→ 8x = 48 cm

→ x = 6cm .

We know that the area of the triangle is half the product of base and height .

• Base = x + 9 = 15cm
• Height = 2x -4 = 8cm .

→ A = 1/2 × b × h

→ A = 1/2 × 8cm × 15cm

→ A = 60cm²

Answer 2

• 102 cm²

Explanation:

Perimeter is:

• P = 40 cm
• and
• P = 2x - 4 + 5x - 13 + x + 9 = 8x - 8

Comparing the value:

• 8x - 8 = 40
• 8x = 48
• x = 8 cm

Are formula:

• A = 1/2ah

Replacing values:

• A = 1/2(x + 9)(2x - 4)
• A = 1/2(8 + 9)(2*8 - 4) = 1/2*17*12 = 102 cm²