Thursday

July 31, 2014

July 31, 2014

Posted by **Knights** on Thursday, March 21, 2013 at 2:14pm.

Please help I do not know how to start....

- Geometry - semicircle inside isosceles triangle -
**Steve**, Thursday, March 21, 2013 at 2:49pmIf the center of the semi-circle is O, draw OD where D is the point where AC is tangent to o the circle.

Since OD┴AD, if the radius is r, let a=AD and b=DC, so a+b=25

r^2 + a^2 =15^2

r^2 + b^2 = 20^2

equating r^2, we get

15^2-a^2 = 20^2-(25-a)^2

solve to get a=9, so b=16

So, r^2+9^2 = 15^2

r^2 = 225-81=144

area of semi-circle is 1/2 pi r^2 = 72pi

- Geometry - semicircle inside isosceles triangle -
**Knights**, Thursday, March 21, 2013 at 4:50pmThanks a lot!

**Related Questions**

Geometry - ABC is a right angled triangle with ∠ABC=90∘ and side ...

Maths - ABC is a right angled triangle with ∠ABC=90∘ and side ...

Math (Geometry) - The perimeter of right triangle ABC is equal to the perimeter ...

9th grade - given that a(-1,8) ,b(2,4) and if the line y=4 is the axis of ...

geometry!!!!!! - ABC is an isosceles triangle with AB = BC. The circumcircle of ...

geometry - how do you find the height of an isosceles triangle only knowing the ...

geometry - The perimeter of right triangle RST is equal to the perimeter of ...

geometry - triangle ABC is an isosceles right triangle. The endpoints of the ...

math - Isosceles Triangle ABC is inscribed in a circle with radius 12cm. Aide AB...

Math - Triangle ABC is circumscribed about circle O and D,E, and F are points of...