it's one of the "Pythagorean triples"
right triangles with integer sides
like 3-4-5
remember ... a^2 + b^2 = c^2
find the length of the hypotenuse of a triangle with legs of 5 ft and 12 ft?
11 ft
13 ft
17 ft
60 ft
2 answers
there are a few basic integer-sided right triangles you would do well to learn. These start with
3-4-5
5-12-13
8-15-17
7-24-25
and all multiples of these, such as
6-8-10, 10-40-50, ...
However, to solve the problem in general, the hypotenuse is
c^2 = a^2+b^2
In your case, we have
c^2 = 5^2 + 12^2 = 25+144 = 169 = 13^2
so, c = 13
3-4-5
5-12-13
8-15-17
7-24-25
and all multiples of these, such as
6-8-10, 10-40-50, ...
However, to solve the problem in general, the hypotenuse is
c^2 = a^2+b^2
In your case, we have
c^2 = 5^2 + 12^2 = 25+144 = 169 = 13^2
so, c = 13
29 answers