Step by step
The question
Question: find out if a triangle with sides 10, 24, 27 is a right triangle.
1 Find the longest side
In a right triangle, the longest side is across from the right angle.
We call it c.
Here it is 27.
The two shorter sides are a and b.
Every right triangle has a² + b² = c².
So we test it.
So c = 27, the longest side.
2 Square the short sides
Now put the numbers in: a = 10 and b = 24.
10² means 10 times 10.
That is 100.
24² means 24 times 24.
That is 576.
Write the squares.
100 plus 576 is 676.
So a² + b² is 676.
3 Square the longest side
Now put the numbers in: c = 27.
27² means 27 times 27.
That is 729.
So c² is 729.
Careful!
c is always the longest side.
Find it first.
4 Compare
a² + b² is 676.
c² is 729.
They are not the same.
So no: it is not a right triangle.
c² is bigger.
So the angle across from c is wider than a right angle.
Let's look back.
First: find the longest side.
Then: square the short sides.
Then: square the longest side.
Last: compare.