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The sides of a triangle are 8 cm, 11 cm and 13 cm. What is its area?

a. 8√30cm²
b. 4√10cm²
c. 3√100cm²
d. 6√200cm²

1 Answer

6 votes

Final answer:

The area of a triangle with sides 8 cm, 11 cm, and 13 cm can be found using Heron's formula. By calculating the semi-perimeter and plugging in the values into the formula, we determine the area is 8√{30} cm², which corresponds to answer choice (a).

Step-by-step explanation:

To find the area of a triangle with sides of lengths 8 cm, 11 cm, and 13 cm, you can use Heron's formula since the triangle is not necessarily a right-angled triangle. First, calculate the semi-perimeter s by adding the lengths of the sides and dividing by 2:

s = (8 + 11 + 13) / 2 = 16 cm

Now, apply Heron's formula to find the area (A):

A = √[s(s - 8)(s - 11)(s - 13)]

Plugging in the values, we get:

A = √[16(16 - 8)(16 - 11)(16 - 13)]

Which simplifies to:

A = √[16(8)(5)(3)]

And further simplifies to:

A = √[1920]

Calculating the square root, you find that the area of the triangle is:

A = 8√{30} cm²

Therefore, the correct answer is (a) 8√{30}cm².

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