Answer:
[tex]\sqrt{5}[/tex]
Step-by-step explanation:
[tex]a^{2} + b^{2} = c^{2}[/tex]
In this situation a = 1, b = 2
[tex]1^{2} + 2^{2} = c^{2}[/tex]
1 + 4 = [tex]c^{2}[/tex]
5 = [tex]c^{2}[/tex]
c = [tex]\sqrt{5}[/tex]
This is an important mathematical theorem to know. It's called the Pythagorean Theorem.
