A circle passes through point (-2, -1) and its center is at (2, -1). Which equation represents the circle?
1 answer:
Answer:
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: F
Step-by-step explanation:
This is basically like 2 rectangles. Find the area of both and add them together.
Remember that the area is x
.
Area of Rectangle 1: = 7,
= 14
14 x 7 = 98
Area of Rectangle 2: = 5,
= 14
14 x 5 = 70
Add the areas together: 98 + 70
= 168
Answer:
option B is correct
Step-by-step explanation:
We have 5 spaces in the license plate:
_ _ _ _ _
we have 26 available letters, and 10 available numbers.
starting with letters:
- how many choices do i have to place the 1st letter? 26.
26 _ _ _ _
- how many choices do i have to place the 2nd letter? 26 (since we're allowed to repeat letters)
26 26 _ _ _
- how many choices do i have to place the 3rd letter? 26
26 26 26 _ _
we've used all the places for letters, (note: the exact position of the letters doesn't matter here, the first letter could've been placed anywhere in _ _ _ _ _, but the amount of possible choices for letters would always be 26).
let's move on to numbers.
- how many choices do i have to place the 1st number? 10
26 26 26 10 _
- how many choices do i have to place the 2nd number? 10
26 26 26 10 10
we've completed our number plate. Next we'll simply multiply all these numbers to get all the possible arrangements in which numbers and letters can be displayed on a license place.
option B is correct