Math is useful in many ways. Math is used in daily life. For example: calculating change, calculating time, being a accountant, working in many jobs. Math is needed for logical problems. Math could also lead you to many different jobs like being a finance ( financial analyst, accountant), technology (data scientist, software engineer, computer programmer), and research (mathematician, statistician, economist). If for some reason you're trying to find the third angle of a right angled triangle you could use the pythagorean theorem, or if you're trying to find missing side lengths or angles in a non-right-angled triangle when you are given specific information, such as two angles and a side, or two sides and a non-included angle, you could use the Sin law.