If a perimeter is 20/21 what is the side length of the square

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

How do i find the missing angle measure in a polygon