URGENT PLEASE HELP SERIOUS ANSWERS ONLY verify 2 csc (2x)=1+ tan^2 x / tan x

Iq scores for adults age 20 to 34 years are normally distributed according to n(120, 20). in what range does the middle 68% of people in this group score on the test?

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

The circumference of a redwood tree trunk is 20π ft, and it is 100 ft tall. what is the approximate volume of the redwood tree trunk? 1,000π ft3 10,000π ft3 4,000π ft3 40,000π ft3