Assuming this is the Pythagorean theorem our formula would be
a^2 + b^2 = c^2
meaning both of those sides multiplied by themselves added together will equal a number which is the result of c multiplied byitself sorry it sounds confused but...
15 × 15 = 225 8 × 8 = 64 225 + 64 = 289
the square root or the (number multiplied byitself that equals 289) is 17 because
The third equation is correct. The easiest way to solve a problem like this is to plug the x-values from the chart into the equations and see which one equals the y-value in the chart.