Question

Q- An iscosceles triangle has perimeter 30 cm and each of equal sides is 12 cm. Find the area of the triangle ?​

Answer 1

Answer:

9√15

Step By Step Explanation

At first we will calculate base(third side) then we will calculate area.

Given that,

Perimeter = 30cm

Side = 12cm

Perimeter = 2a + b

Substitute the known value in the above formula

⟹ 30 = 2(12) + b

⟹ 24 + b = 30

⟹ b = 30 - 24

⟹ b = 6

Now, calculating area

Semi Perimeter(s) = (a+b+c)/2

= (12+12+6)/2

= 30/2 = 15.

By Heron's formula, we get

A = √s(s-a) (s-b) (s-c)

Substitute values

⟹ A = √15(15-12) (15 - 12) (15 - 6)

⟹ A = √15 × 3 × 3 × 9

⟹ A = √15 × 9 × 9

⟹ A = √9² × √15

⟹ A = 9√15cm² ≈ 35cm².

Therefore, area is 9√15cm².

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Answer 2

Answer:

Answer:

$\huge{ \boxed{\tt{9√15}}}$

Step By Step Explanation

At first we will calculate base(third side) then we will calculate area.

Given that,

Perimeter = 30cm

Side = 12cm

Perimeter = 2a + b

Substitute the known value in the above formula

⟹ 30 = 2(12) + b

⟹ 24 + b = 30

⟹ b = 30 - 24

⟹ b = 6

Now, calculating area

Semi Perimeter(s) = (a+b+c)/2

= (12+12+6)/2

= 30/2 = 15.

By Heron's formula, we get

A = √s(s-a) (s-b) (s-c)

Substitute values

⟹ A = √15(15-12) (15 - 12) (15 - 6)

⟹ A = √15 × 3 × 3 × 9

⟹ A = √15 × 9 × 9

⟹ A = √9² × √15

⟹ A = 9√15cm² ≈ 35cm².

Therefore, area is 9√15cm².

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