A circle passes through point (-2, -1) and its center is at (2, -1). Which equation represents the circle?

Mathematics

1 answer:

Anastaziya [24]3 years ago

7 0

Answer:

$\text{A)}\qquad (x-2)^2+(y+1)^2=16$

Step-by-step explanation:

The formula for a circle of radius r centered at (h, k) is ...

(x -h)^2 +(y -k)^2 = r^2

Both of the given points are on the line y=-1. The distance between them is the difference of their x-coordinates, 2 -(-2) = 4. So, the radius of the circle is 4 and the equation becomes ...

(x -2)^2 +(y -(-1))^2 = 4^2

(x -2)^2 +(y +1)^2 = 16 . . . . . . . . . matches choice A

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Answer:

1. 121 π unit²

2. 143°

3. 151 unit²

Step-by-step explanation:

Area of a circle is given by the formula A = πr²

where

A is the area,

r is the radius of the circle

From the given diagram, we can see that the radius is 11, hence the area will be:

$A=\pi r^2\\A=\pi (11)^2\\A=121\pi$

The answer is $121\pi$ units^2

The unshaded secctor and the shaded sector equals the circle. We know that circle is 360°. The unshaded sector has an angle of 217°. So the shaded part will be 360 - 217 = 143°

The measure of the central angle of the shaded sector is 143°

Area of a sector is given by the formula $A=\frac{\theta}{360}*\pi r^2$