# Thread: I need help constructing a triangle!!!!

1. ## I need help constructing a triangle!!!!

construct triangle from side a, angle (alpha), and radius.
(but, keep only a part of the condition, drop the other part: disregard the radius, but keep side a and angle (alpha), what is the locus of the center of the inscribed circle?)

thanks everyone

2. Originally Posted by joesmith13610
construct triangle from side a, angle (alpha), and radius.
(but, keep only a part of the condition, drop the other part: disregard the radius, but keep side a and angle (alpha), what is the locus of the center of the inscribed circle?)

thanks everyone
I assume that the angle $\displaystyle \alpha$ is opposite the side a.

If so:

1. Draw the side a which has the endpoints B and C.

2. Draw the perpendicular bisector of a.

3. Draw in B (or C) the angle $\displaystyle 90^\circ - \alpha$ with a as one leg.

4. The other leg of the angle cuts the perpendicular bisector in M, the midpoint of the circumscribed circle.

5. Have a look here: Central Angle Theorem - Math Open Reference

3. thank you.

I'll give this a try.