Answer:
2[tex]\sqrt{10}[/tex]
Step-by-step explanation:
You can get this by using the Pythagorean Theorem
a^2 + b^2 = c^2
where a and b are the legs and c is the hypotenuse
3^2 + b^2 = 7^2
9 + b^2 = 49
b^2 = 40
sqrt of both sides
b = [tex]\sqrt{40}[/tex]
b = 2[tex]\sqrt{10}[/tex]
if this helps please give me brainliest