(Geometry: points in triangle?) C++ program

Suppose a right triangle is placed in a plane as shown below. The right-angle point is placed at (0, 0), and the other two points are placed at (200, 0), and (0, 100). Write a C++ program that

prompts the user to enter a point with x - and y -coordinates and determines whether the point is inside the triangle

.

Here are some sample runs: Enter a point's x- and y-coordinates: 100.5 25.5

The point is in the triangle

Enter a point's x- and y-coordinates: 100.5 50.5

The point is not in the triangle

(0,100) p2 opl (0,0) (200, 0)