How can you find what is 2/5 of 100?

2     100 200
_ *.  ___+___= 40
5.       1.  5

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .