Answer:Third side = 4
Explanation:
You already have the points for a and b(The sides that are already listedare called a and b). Now we can use the puthagorean theorem a²+b²=c².
Plug in a and B: 3² + (√7)² = c²
Simplify: 9+ 7 = c²
Simplify: 16=c²
square root each side: 4=c