What are the first 3 terms of the sequence represented by the expression n[n-1]-4 the first term is when n=1

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?

If a distance of 75 yds is measured back from the edge of the canyon and two angles are measured , find the distance across the canyon angle acb = 50° angle abc=100° a=75 yds what does c equal?