Answer:
A = 388.58 cm^2
Step-by-step explanation:
For a cone whose base has a radius R, and a hypotenuse S, the area is:
A = pi*R^2 + pi*R*S
Where pi = 3.14
In this case, we can see that the diameter is: 15cm
Then the radius, half of the diameter, is:
R = 15cm/2 = 7.5cm
The hypotenuse is 9cm, then S = 9cm
A = 3.14*(7.5cm)^2 + 3.14*(9cm)*(7.5cm) = 388.575 cm^2
Rounding to two decimal places, we need to look at the third one, which is a five, so we need to round up:
A = 388.58 cm^2
It takes 1.5 hours for 4 workers to paint the same room
<em><u>Solution:</u></em>
Given that 3 workers can paint a room in 2 hours
To find: Time taken for 4 workers to paint the same room
Assume the time needed to paint the room is inversely proportional to the number of worker
Where, "k" is the constant of proportionality
<em><u>3 workers can paint a room in 2 hours</u></em>
Substitute number of workers = 3 and time = 2 hours
Therefore,
To find time taken for 4 workers to paint the same room, substitute number of workers = 4 in above expression
Thus it takes 1.5 hours for 4 workers to paint the same room