# Math. I really don't get this question

posted by .

three circles are manually tangent externally. their centers form a triangle whose sides are of length 8, 9, 13. find the total area of the three circles

• Math. I really don't get this question -

If the radii of the circles are x,y,z then each side of the triangle is the sum of two of the radii. So,

x+y=8
x+z=9
y+z=13
(x,y,z) = (2,6,7)

Since the area of a circle is πr^2, the area of all of the circles is
π(2^2+6^2+7^2) = 89π

## Similar Questions

1. ### geometry

Three circles are externally tangent to one another. The radius of each of the circles is 2 cm. A belt fits tightly around the three circles. Find the length of the belt. Express your answer in terms of pi with an explanation.

PLEASE HELP I REALLY NEED HELP. Each of the three circles in the figure below is externally tangent to the other two, and each side of the triangle is tangent to two of the circles. If each circle has radius three, then find the perimeter …
3. ### Trig

Three circles with radii of 4, 5, and 6 cm, respectively, are tangent to each other externally. Find the angles of the triangle whose vertexes are the centers of the circles.
4. ### Geometry/Trigonometry

Circles with centers (2,1) and (8,9) have radii 1 and 9, respectively. The equation of a common external tangent to the circles can be written in the form y=mx+b with m < 0. What is b?
5. ### Haley

Three circles with radii 35cm, 50cm, and 65cm respectively are tangent to each other externally. Find the angles of the triangle formed by joining the centers of the circles. My teacher said to use the cosine law cause you know 3 sides …
6. ### geometry

Two circles which are not congruent touch externally. the sum of their area is 130¦Ðcm.square and distance between their centers is 14 cm. find radii of circles.
7. ### Mathematics

Three circles touch each other externally. Their centres make a triangle with sides of 11cm, 15cm and 19cm. What are the radii of the three circles?
8. ### Maths

Three circles of unit radii touch each other externally. They are inscribed in triangle. What will the area after leaving the area of those circles.
9. ### Geometry

Three circles touch one another externally.Their centres form A triangle with sides 10cm,9cm and 7cm.Find the radii of the circles
10. ### Math

Three circles which touch each other externally with the center of the circles at A, B, C form a triangle with size of 9cm, 7cm, 6cm.calculate the radii of the circle

More Similar Questions

Post a New Question