The converse of Pythagorean Theorem is also
true. That is, if a triangle satisfies Pythagoras’
theorem, then it is a right triangle. Put it
another way, only right triangles will satisfy
Pythagorean Theorem. Now, on a graph paper
ask the students to make two lines. The first
one being three units in the horizontal
direction, and the second being four units in
perpendicular (i.e. vertical) direction, with the
two lines intersect at the end points of the two
lines. The result is right angle. Ask thestudents to connect the other two ends (open)
of the lines to form a right triangle. Measure
this distance with a ruler, see the Figure below.