Answer:s = 16.97 unitsStep-by-step explanation:Since this is a right triangle, we can use trigonometry to figure out the lengths of the sides.Look at the 45 degree angle. We can use the opposite side (12) and the hypotenuse (s) to solve for s.Opposite and hypotenuse is sine, so we are using sine. The sine of 45 degrees is 0.70710678118. Make an equation like so:0.70710678118 = [tex]\frac{12}{s}[/tex], and we are solving for s.Put a 1 in the denominator of sine(45 degrees) so you can cross-multiply.[tex]\frac{0.70710678118}{1} =\frac{12}{s}[/tex]Cross multiply.0.70710678118s = 12Divide both sides by sine(45 degrees).s = 16.97The length of side s is 16.97 units.Another way to have done this problem is to use the Pythagorean theorem: a^2 + b^2 = c^2Substitute 12 for a and b and solve for c, the hypotenuse.(12)^2 + (12)^2 = c^2Evaluate the exponents.144 + 144 = c^2Add them together.288 = c^2Square root 288 to solve for c.c = 16.97, which is the same answer as you got using trigonometry.