Use geometry words to describe a way to separate triangles into other triangles?

Let us suppose we have a triangle ABC as shown in the attached image.

Now, let us we draw a  perpendicular line from the vertex A to the base BC. Let the line meets the base BC at D.

Then, this perpendicular line AD will separate the triangle  ABC into two right angle triangle ADB and triangle ADC.

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0