wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The centre of a circle is (2a, a-7). Find the values of a if the circle passes through the point (11, -9) and has diameter 102 units.

Open in App
Solution

The distance of the centre of the circle from any point on the circle is the radius of the circle where the radius is half of the diameter.
Radius = fraction numerator 10 square root of 2 over denominator 2 end fraction ---- (i)
Radius = square root of left parenthesis 2 a minus 11 right parenthesis squared plus left parenthesis a minus 7 plus 9 right parenthesis squared end root ---- ii
From (i) and (ii)

square root of left parenthesis 2 a minus 11 right parenthesis squared plus left parenthesis a minus 7 plus 9 right parenthesis squared end root = fraction numerator 10 square root of 2 over denominator 2 end fraction
Square both sides,
4 a squared plus 121 minus 44 a plus a squared plus 4 plus 4 a equals 50 5 a squared minus 40 a plus 75 equals 0 a squared minus 8 a plus 15 equals 0 a squared minus 3 a minus 5 a plus 15 equals 0 a left parenthesis a minus 3 right parenthesis minus 5 left parenthesis a minus 3 right parenthesis equals 0 left parenthesis a minus 5 right parenthesis left parenthesis a minus 3 right parenthesis equals 0 a equals 5 comma 3


flag
Suggest Corrections
thumbs-up
285
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Distance Formula
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon