given the length of three sides of a triangle, which is a right triangle?
(1) 10,26,24
(2) 20,12,18
(3) 30,15,26
(4) 40,50,80
and also explain why it is the answer.

Pythagorean Theorem: 
c represents the longest side of the triangle
If the triangle is a right triangle, the Pythagorean theorem will be true.

(1) 10,24,26



Right Triangle

(2) 12,18,20



Not a right triangle

(3) 15,26,30



Not a right triangle

(4) 40,50,80



Not a right triangle

#1 is a right triangle

Ais the correct answer