Hi, I need help with these questions(adsbygoogle = window.adsbygoogle || []).push({});

Given the endpoints of a diameter, write an equation for the circle.

a) (-3,5) and (1,3)

I tryed this

m= (x1+x2)/2, (y1+y2)/2

= (-3+1)/2 , (5+3)/2

= -2/2, 8/2

= (-1,4)

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

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

(1+1)^2 + (3-4)^2=r^2

(2)^2 + (-1)^2=r^2

5=r^2

so, (x+1)^2 + (y-4)^2 = 5

but, this answer in the back of the book is different so can someone tell me what to do?

and

1. how do you simplify root 50

2. is rise y and run x?

***

when a stone is dropped in a lake, circular waves or ripples are created. The enrey point of the stone marks the center of the circles. Suppose the radious increases at the reate of 20cm/s. write anequation for the outermost circle 2.5s after the stone hits the water.

20*2.5=50cm

X^2 + Y^2=50^2

X^2 + Y^2=2500

is that right?

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# Homework Help: Write an equation for the circle

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