Question

Which of the following is the equation of a circle whose center is at the origin and whose radius is 5 ?

x(squared) + y(squared) =√5

x(squared) + y(squared) = 5

x(squared) + y(squared) = 10

x(squared) + y(squared) = 25

Answer 1

@peachpi I don't understand how to do this one!

Answer 2

the equation whose centre is at the origin and whose radius is r is

x^2 + y^2 = r^2

Answer 3

now substitute for r = sqrt5 and you have it

Answer 4

I got 5

Answer 5

you got 5 for what - i think you are on the right track

Answer 6

you need the correct value for r^2

Answer 7

so then would It be √5?

Answer 8

√5? is given in the question. its the radius ( r ) of the circle.

Answer 9

so it √5 is r what is r^2?

Answer 10

* if

Answer 11

r^2 = √5 * √5 = ?

Answer 12

what does ^ mean?

Answer 13

@welshfella

Answer 14

10?

Answer 15

^ means 'to the power' or exponential

r^2 = r * r

Answer 16

the square root of some number times the square root of the number = the number
( by definition)

so sqrt 3 * sqrt 3 = 3