What equation does the image represent?

(a)  

What equation does the image represent?

(a)  

The positive number that satisfies

(a)  

A set of three positive integers  $a,\ b,\ and\ c$  that satisfy the equation  $c^2=a^2+b^2$  

(a)  

lines that never intersect and are always the same distance apart

(a)  

Lines that intersect at a right angle

(a)  

two ratios that are set equal to each other.

(a)  

A segment that joins two nonconsecutive vertices

(a)  

Two consecutive angles whose common side is a base

(a)