Using the formula for the area of a sector, solve for the area of a sector with an angle of 135° and a radius of 13 in.(1 point)

Responses

A=30.6 in.2
upper A equals 30.6 in. squared

A=530.9 in.2
upper A equals 530.9 in. squared

A=199.1 in.2
upper A equals 199.1 in. squared

A=398.2 in.2
upper A equals 398.2 in. squared

1 answer

To find the area \( A \) of a sector, you can use the formula:

\[ A = \frac{\theta}{360^\circ} \times \pi r^2 \]

where:

  • \( \theta \) is the angle in degrees,
  • \( r \) is the radius.

For this problem, the angle \( \theta = 135^\circ \) and the radius \( r = 13 \) in.

Now, substitute the values into the formula:

\[ A = \frac{135}{360} \times \pi \times (13)^2 \]

First, calculate \( (13)^2 \):

\[ (13)^2 = 169 \]

Now plug that into the formula:

\[ A = \frac{135}{360} \times \pi \times 169 \]

Simplifying \( \frac{135}{360} \):

\[ \frac{135}{360} = \frac{135 \div 45}{360 \div 45} = \frac{3}{8} \]

So, we have:

\[ A = \frac{3}{8} \times \pi \times 169 \]

Using \( \pi \approx 3.14159 \):

\[ A \approx \frac{3}{8} \times 3.14159 \times 169 \approx \frac{3 \times 3.14159 \times 169}{8} \]

Calculating the area step-by-step:

  1. Calculate \( 3 \times 3.14159 \): \[ 3 \times 3.14159 \approx 9.42477 \]

  2. Multiply by \( 169 \): \[ 9.42477 \times 169 \approx 1591.15653 \]

  3. Divide by \( 8 \): \[ \frac{1591.15653}{8} \approx 198.89456625 \]

So, rounding this value gives us:

\[ A \approx 198.9 , \text{in}^2 \]

When comparing with the options given, the closest value is:

A = 199.1 in.²

Therefore, the correct response is:

A = 199.1 in.²