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Sides of a triangle are in the ratio 12:...

Sides of a triangle are in the ratio `12:17:25` and its perimeter is `540 cm.` Its area will be-

A

`6000cm^(2)`

B

`9000cm^(2)`

C

`12000cm^(2)`

D

None of these

Text Solution

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The correct Answer is:
To find the area of a triangle with sides in the ratio 12:17:25 and a perimeter of 540 cm, we can follow these steps: ### Step 1: Determine the sides of the triangle Let the sides of the triangle be represented as: - \( A = 12k \) - \( B = 17k \) - \( C = 25k \) Given that the perimeter is 540 cm, we can set up the equation: \[ A + B + C = 540 \] Substituting the values: \[ 12k + 17k + 25k = 540 \] ### Step 2: Solve for \( k \) Combine the terms: \[ 54k = 540 \] Now, divide both sides by 54: \[ k = \frac{540}{54} = 10 \] ### Step 3: Calculate the lengths of the sides Now, substitute \( k \) back into the expressions for the sides: - \( A = 12k = 12 \times 10 = 120 \, \text{cm} \) - \( B = 17k = 17 \times 10 = 170 \, \text{cm} \) - \( C = 25k = 25 \times 10 = 250 \, \text{cm} \) ### Step 4: Calculate the semi-perimeter The semi-perimeter \( s \) is given by: \[ s = \frac{A + B + C}{2} = \frac{540}{2} = 270 \, \text{cm} \] ### Step 5: Apply Heron's formula to find the area Heron's formula for the area \( A \) of the triangle is: \[ \text{Area} = \sqrt{s(s - A)(s - B)(s - C)} \] Substituting the values we have: \[ \text{Area} = \sqrt{270 \times (270 - 120) \times (270 - 170) \times (270 - 250)} \] Calculating each term: - \( s - A = 270 - 120 = 150 \) - \( s - B = 270 - 170 = 100 \) - \( s - C = 270 - 250 = 20 \) Now substituting these values back into the area formula: \[ \text{Area} = \sqrt{270 \times 150 \times 100 \times 20} \] ### Step 6: Simplify the expression under the square root Calculating the product: \[ 270 \times 150 = 40500 \] \[ 40500 \times 100 = 4050000 \] \[ 4050000 \times 20 = 81000000 \] So we have: \[ \text{Area} = \sqrt{81000000} \] Breaking it down: \[ \sqrt{81000000} = \sqrt{81 \times 10^6} = 9 \times 1000 = 9000 \, \text{cm}^2 \] ### Final Answer Thus, the area of the triangle is: \[ \text{Area} = 9000 \, \text{cm}^2 \]
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