Can someone help me understand how to solve 4 please. Would really appreciate it.

The length of RT from the figure is 8 units
In order to find the measure of RT, we will use the pythagoras theorem. According to the theorem;
hypotenuse² = adjacent² + opposite²
From the given figure;
ST = hyp = 10
RS = adj = 6
Find RT
RT = √10² - 6²
RT = √100 - 36
RT = √64
RT = 8 units
Hence the length of RT from the figure is 8 units
Learn more on pythagoras theorem here: https://brainly.com/question/343682