Make up a right triangle 12cm, 15cm, and 20cm?
unit 3 page 43
That may not form a right triangle. First I'll try to draw
it as accurately to scale as possible to see whether a
triangle with those lengths as sides looks like it could
form a right triangle. Here is such an accurately drawn
triangle:
It looks like it is not quite a right triangle because
the angle at the lower right looks a little too large to
be 90° and more like about 95°. But looking and seeing
is not considered good math, so we will have to use the
formula from the Pythagorean theorem. If it were a
right triangle the longest side 20 cm would have to be
the hypotenuse. so we would have to have that
c² = a² + b²
20² = 12² + 15²
400 = 144 + 225
400 = 369
No that's false, so it isn't a right triangle.
Edwin
