In ∆abc, the altitudes from vertex b and c intersect at point m, so that bm = cm. prove that ∆abc is isosceles.

When you are making a circle graph by hand, how do you convert a number for a part into its corresponding angle measure in the circle graph? when you are making a circle graph by hand, what should you do if one of your angle measures is greater than 180°?

3382-299=3383- ? fill in the blank?

Find the solution of this system of equation -7x+y=-20 9x-3y=36