## anonymous one year ago Points A(−1, 2), B(−2, −5) and C(7, −2) are on a circle. What is the area of the circle? Express your answer as a decimal to the nearest tenth.

1. anonymous

1. slope of AB 2. mid point of A,B 3. slope of line perpendicular to AB 4. eq. of line (perpendicular bisector) through mid point 5. similarly find the eq. of perpendicular bisector of BC 6. center is point of intersection of perpendicular bisectors (say O) 7.find r=OA 8. area of circle.

2. anonymous

$slope=\frac{ y _{2}-y _{1} }{ x _{2} -x _{1}}$

3. anonymous

mid point$=\left( \frac{ x _{1} +x _{2}}{ 2 } ,\frac{ y _{1} +y _{2}}{ 2 }\right)$

4. anonymous

can you help me i dont know what you are talking about can you give me the answer too @surjithayer

5. anonymous

first find the slope of AB by the above formula and show me.

6. anonymous

$m=\frac{ -5-2 }{ -2-(-1) }=\frac{ -7 }{ -2+1 }=\frac{ -7 }{ -1 }=7$ slope of line perpendicular to AB=-1/m=-1/7

7. anonymous

mid point of A,B

8. anonymous

will you show me ?