Question 578023
In right triangles the pythagorean theorem tells us that:

a^2 + b^2 = c^2

4^2 + 3^2 = c^2

16 + 9 = c^2

25 = c^2
{{{sqrt( 25 ) = sqrt( c^2 )}}}

c = 5

3,4,5 is a special case of right triangles, good to memorize