Answer:Rhombuses :)
Step-by-step explanation:
If it takes one person 4 hours to paint a room and another person 12 hours to
paint the same room, working together they could paint the room even quicker, it
turns out they would paint the room in 3 hours together. This can be reasoned by
the following logic, if the first person paints the room in 4 hours, she paints 14 of
the room each hour. If the second person takes 12 hours to paint the room, he
paints 1 of the room each hour. So together, each hour they paint 1 + 1 of the 12 4 12
room. Using a common denominator of 12 gives: 3 + 1 = 4 = 1. This means 12 12 12 3
each hour, working together they complete 13 of the room. If 13 is completed each hour, it follows that it will take 3 hours to complete the entire room.
This pattern is used to solve teamwork problems. If the first person does a job in A, a second person does a job in B, and together they can do a job in T (total). We can use the team work equation.
Teamwork Equation: A1 + B1 = T1
Often these problems will involve fractions. Rather than thinking of the first frac-
tion as A1 , it may be better to think of it as the reciprocal of A’s time.
World View Note: When the Egyptians, who were the first to work with frac- tions, wrote fractions, they were all unit fractions (numerator of one). They only used these type of fractions for about 2000 years! Some believe that this cumber- some style of using fractions was used for so long out of tradition, others believe the Egyptians had a way of thinking about and working with fractions that has been completely lost in history.
and inner radius 
![\displaystyle V = \int_0^1 \pi\Big[ \left( 2 - x^2 \right)^2 - \left( 2 - \sqrt{x}\right)^2\Big] dx](https://tex.z-dn.net/?f=%5Cdisplaystyle%20V%20%3D%20%5Cint_0%5E1%20%5Cpi%5CBig%5B%20%5Cleft%28%202%20-%20x%5E2%20%5Cright%29%5E2%20-%20%5Cleft%28%202%20-%20%5Csqrt%7Bx%7D%5Cright%29%5E2%5CBig%5D%20dx)
