7th Grade Math
posted by Elizabeth on .
Find the area of the circle described. Use pi= 22/7.
Diameter= 1.4cm
Please help!

Area = pi * r^2
Radius = 0.7 or 7/10
A = 22/7 * 49/100
A = 1078/700
A = 1 54/100 = 1 27/50 square centimeters 
the circumference of a circle and the perimeter of a square are both 40 cm. which has a greater are.the circle or the square?find the circumference

First, if you have a question, it is much better to put it in as a separate post in <Post a New Question> rather than attaching it to a previous question, where it is more likely to be overlooked.
Second, you have already stated the circumference of the circle.
If the perimeter of a square = 40 cm, each side must 10 cm, giving you an area 10*10 = 100 cm.
Circle circumference = π d = 40, where d = diameter
Therefore d = 40/π
Circle area = 1/4 π d^2 = 1/4 π (40/π)^2
Insert d value from first equation into the second, solve for area and compare to square area. 
if its the diamater you just cut that in half to make the radius then you do that times pie which is 3.14 or 22/7. you welcome(: