Working together, Rocco and Giulia can paint a room in 3 hours. It would have taken Rocco 7 hours to do the job alone. Which equation can be used to determine r, Giulia’s rate of work in parts per hour?

4/21  a room per hour

Step-by-step explanation:

Rocco :

7hours———> whole room

then

in 1h ———-> 1/7 of the whole room

then

in 3h ———-> 3/7 of the whole room

therefore

Giulia will finish 4/7 of the whole room in 3h

finally,

circle area = pi * radius^2

if diameter = 10 then radius = 5

circle area = pi * 5^2

circle area = pi * 25

circle area = 78.5398163397 square units

step-by-step explanation: