SOLUTION: PQR is an isosceles triangle with a base of 18 cm and sides of 15 cm and is inscribed in a circle with its vertices touching the circumference of the circle. The radius, in centime

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Question 1195527: PQR is an isosceles triangle with a base of 18 cm and sides of 15 cm and is inscribed in a circle with its vertices touching the circumference of the circle. The radius, in centimetres, of the circle is?
Found 2 solutions by ikleyn, ankor@dixie-net.com:
Answer by ikleyn(52786)   (Show Source):
You can put this solution on YOUR website!
.

In Math, questions in problems are NEVER formulated in the form as you do.

As you present your problem, it causes a shudder.

        It would never occur to anyone, who writes
        mathematical problems, to write in this form.

May be, this tone is appropriate when you communicate with your dogs in your home,
but it is not appropriate when you communicate with other people.

Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website!
PQR is an isosceles triangle with a base of 18 cm and sides of 15 cm and is inscribed in a circle with its vertices touching the circumference of the circle. The radius, in centimetres, of the circle is?
:
draw this out, assume the base of the triangle (18cm) is below the center
Find the height of the triangle using pythag;
h goes thru the center.
h =
h = 12 cm
:
let x = dist from the center to the center of the base, then we have
r = 12 - x
drawn a right triangle using the radius (r), x and half the base (9), find r
r =
:
r = r therefore
= 12 - x
square both sides

x^2 drops out
81 = 144 - 24x
24x = 144 - 81
24x = 63
x = 63/24
x = 2.625
find the radius
r = 12 - 2.625
r = 9.325