HOMEWORK NEED HELP (Gr.8 math)?

Question

This is my math quesion..
'Calculate the area of a circle with each of these measurments'
a) The DIAMETRE is 7.3 cm.
b) The RADIUS is 2cm.
SO all i have to do is find the area of the cicle..,
could someone please give me the formulas?

Answer 1

Part a)
r = 3.65 cm
A = π r² = π (3.65)² cm²
A = 41.9 cm² (to 1 dec. place)

Part b)
A = π x 2² cm²
A = 4π cm²
A = 12.6 cm² (to 1 dec. place)

Answer 2

A = Pi r ^2

meaning:
a) if the diametre is 7.3 then the radius is 3.65. plug it into the formula above and you should obtain
41.85 as your area

b) do the same and your answer should be 12.57

Answer 3

Area = pi * radius^2 (note: pi is a constant that is approximately 3.14)

A. 7.3/2 = 3.65 divide by 2 to calculate radius
A = pi * (3.65^2) = 41.85 plug in formula
B. A = pi * (2^2) = 4pi = 12.57

Answer 4

Sure!
Area = pi times the square of the radius
So for a) 3.14 X 3.65 x 3.65
and b) 3.14 X 2 x 2

Answer 5

Area = pi*r^2 (hopefully your teacher has gone over Pi by now)
a) Diameter = 7.3 cm, radius = 7.3/2= 3.65 cm
Area = pi*3.65^2
b) Area = pi*4

Answer 6

Pi times radius squared

3.14 times 4 = 12.56

Answer 7

Any term in a linear sequence (ie the place the version between the words is an identical) may well be written as an + b a = the version between each and each term replace a in for the 1st term (the place n = a million) and set equivalent to the fisrt term to discover b. a million,3,5,7,9 enable Sn = the nth term of he sequence distinction between the words is two so an + b a = 2 2n + b = Sn 2(a million) + b = a million so b = -a million Sn = 2n - a million Your solutions are all splendid :-)

Answer 8

A = πr^2, C = 2πr, 2r = d

where r = radius, d = diametre, A = area, C = circumference,
π = C/d ≈ 3.14159...

Answer 9

A = pr2

A=Area
p=perimeter
r2= radius squared

If you have doubts go to the following web site:

http://math.about.com/library/blmeasurement.htm