There is a right angle triangle inside a circle of diameter 18cm. Inside this triangle ,there is another circle of diameter 6 cm. Find the perimeter of the triangle.
Select the correct option:  A) 24cm  B) 36*2^1/2cm  C) 36cm  D) 54cm  E) 42cm
1)The radius of the incircle of a right triangle with legs a and b and hypotenuse c is r=(a+b-c)/2   2)The radius of the circumcircle is half the length of the hypotenuse R=c/2   3)Thus the sum of the circumradius and the inradius is half the sum of the legs R+r=(a+b)/2   From 2nd Rule c=18cm   From 3rd Rule a+b= 2*(9+3)= 
<gadget id="calculator">2*(9+3)</gadget>
<output>24</output>
24cm   Hence Perimeter a+b+c= 24+18= 
<gadget id="calculator">24+18</gadget>
<output>42</output>
42 cm   ANSW42cmR:42cm
<result>E</result>
There is a right angle triangle inside a circle of diameter 18cm. Inside this triangle ,there is another circle of diameter 6 cm. Find the perimeter of the triangle.