What's the answer of 1+2+3+4+5+6+7+8+9+10? I will choose the brainleist answer for the one who can explain the answer.​

This stem-and-leaf plot represents the heights of the students on ralph's basketball team. one student's height is missing from the plot. if the mean height of all the students on the team is 61 inches, what is the missing height? a. 55 in. b. 59 in. c. 61 in. d. 65 in.

What is the distance between point a and b

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota