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Find the area of a triangle : whose th...

Find the area of a triangle :
whose three sides are 17 cm, 8 cm and 15 cm long.
Also, in part (ii) of the question, calculate the length of the altitude corresponding to the largest side of the triangle.

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The correct Answer is:
To find the area of the triangle with sides 17 cm, 8 cm, and 15 cm, we will use Heron's formula. Here’s a step-by-step solution: ### Step 1: Identify the sides of the triangle Let: - Side A = 8 cm - Side B = 17 cm - Side C = 15 cm ### Step 2: Calculate the semi-perimeter (S) The semi-perimeter \( S \) is calculated using the formula: \[ S = \frac{A + B + C}{2} \] Substituting the values: \[ S = \frac{8 + 17 + 15}{2} = \frac{40}{2} = 20 \text{ cm} \] ### Step 3: Apply Heron's formula to find the area (A) Heron's formula states: \[ \text{Area} = \sqrt{S \times (S - A) \times (S - B) \times (S - C)} \] Substituting the values: \[ \text{Area} = \sqrt{20 \times (20 - 8) \times (20 - 17) \times (20 - 15)} \] Calculating each term: \[ = \sqrt{20 \times 12 \times 3 \times 5} \] ### Step 4: Simplify the expression Calculating the product: \[ = \sqrt{20 \times 12 \times 3 \times 5} \] Breaking it down: \[ = \sqrt{(2 \times 2 \times 5) \times (2 \times 2 \times 3) \times 3 \times 5} \] \[ = \sqrt{(2^4) \times (3^2) \times (5^2)} \] Taking the square root: \[ = 2^2 \times 3 \times 5 = 4 \times 3 \times 5 = 60 \text{ cm}^2 \] ### Step 5: Calculate the altitude corresponding to the largest side The largest side is 17 cm. The area can also be expressed as: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \] Let \( h \) be the height corresponding to the base of 17 cm: \[ 60 = \frac{1}{2} \times 17 \times h \] Rearranging gives: \[ h = \frac{60 \times 2}{17} = \frac{120}{17} \approx 7.06 \text{ cm} \] ### Final Answers 1. The area of the triangle is \( 60 \text{ cm}^2 \). 2. The length of the altitude corresponding to the largest side is approximately \( 7.06 \text{ cm} \). ---
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