Answer:
x=12.727822
Explanation:
Since we know two of the angles, we can find the third. 180-90-45=45. This means the two sides of the triangle are also equal, and we know the hypotenuse is 18. So we can use the Pythagorean theorem.
x²+x²=18²
2x²=324
x²=162
x=√162
x=12.727822