Find the coordinates of the circumcentre of the triangle whose vertices are (2,-2),(8,6) and (8,-2). Also find the circum radius of the triangle.
asked Jun 29, 2016 in Word Problem Answers by anonymous

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:

To avoid this verification in future, please log in or register.

1 Answer

The circumcentre of the triangle is the centre of the circle, O,  passing through all three points.

Standard equation for circle: (x-h)^2+(y-k)^2=r^2. (h,k) is O.


So, (6-k)^2-(2+k)^2=0; (6-k-2-k)(6-k+2+k)=0=8(4-2k) and k=2.

(2-h)^2-(8-h)^2=0=-6(10-2h), and h=5, so O is (5,2).

r^2=(2-5)^2+(2+2)^2=9+16=25, and r=5, the circumradius.

Equation of circle is (x-5)^2+(y-2)^2=25.


Put x=2 or 8: 9+(y-2)^2=25; y-2=±4, so y=-2, 6 are solutions and (2,-2), (8,-2) and (8,6) are points on the circumference.

answered Jun 29, 2016 by Rod Top Rated User (487,100 points)
Welcome to, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
79,821 questions
83,639 answers
66,561 users