The longest side of a right triangle is always directly across from the 90 degree angle. This side is called the hypotenuse.
The other two sides are often called
the legs. For now, it really doesn't
matter which one of the legs you call
a or b, as long as you make one a
and the other b.
Because the 3-4-5 right triangle is simple to work with,
let's use it to show how the Pythagorean formula
verifies that a triangle is a right triangle.
Since the numbers on both sides of the = mark are the same, the 3-4-5 triangle is a right triangle.
Please note: The Pythagorean formula is a rule! To verify that a triangle is a right triangle, use the formula.
If the numbers on each side of the = sign are equal, then the triangle is a right triangle.
Right triangle practice: Check these triangles to see which ones are right triangles.
a b c a b c
(1) 6 8 10 (6) 9.99 13.32 16.65
(2) .48 .64 .8 (7) 4.5 6 7.5
(3) 1 1 1 (8) 7 10 13
(4) 8 6 10 (9) 9 2.5 13
(5) 120 160 200 (10) 2 2.6666 3.3333
Lower case letters (a, b, c)
are used as variables for the sides.
Upper case letters (A, B, C)
are used for the angles opposite