How do you find m for (4,2) and (1,4)

Me asap! what is the slope of this line? enter your answer in the box.

Television sizes are based on the length of the diagonal of the television's rectangular screen. so, for example, a 70-inch television is a television having a diagonal screen length of 70 inches. if a 70 inch television's diagonal forms a 29°angle with the base of the screen, what is the vertical height (1) of the screen to the nearest inch? 70 inhin

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?