Answer: X = 35.7° (approximately)
Step-by-step explanation: What we have here is a right angled triangle with two sides given. That means we can apply trigonometrical ratios to calculate any of the angles as well as the unknown side of the triangle.
The unknown angle, X shall be the reference angle in this particular question. The side that lies between the right angle and the reference angle is the adjacent, while the one facing the reference angle is the opposite. So we have the hypotenuse already, that is, the longest side, (or the side facing the right angle).
Since we have been given the opposite side (7 units) and the hypotenuse (12 units) we can conveniently apply the sine ratio, which is
Sin X = opposite/hypotenuse
Sin X = 7/12
Sin X = 0.5833
By checking with your table of values, or by using your calculator, we can now find the value of 0.5833
X = 35.65
Rounded off to the nearest tenth of a degree,
X = 35.7°