# Mary wants to calculate the cost of making and decorating a circular cake. She will put a uniform layer of icing on the outside and inside walls, and the top of the cake. for decoration, a...

Mary wants to calculate the cost of making and decorating a circular cake. She will put a uniform layer of icing on the outside and inside walls, and the top of the cake.

for decoration, a chocolate string will go on the tope circumference of her cake, including enogh to go around the center opening. calculate the total cost to make and decorate Mary's cake. show your work

Batter=\$0.004 per in.3

icing=\$0.01 per in.2(uniform layer)

Chocolate string=\$0.39 per ft (sold in one foot lenghs)

could you explain this question step by step pl thankyouand i need this answer for now thankyou

cburr | Certified Educator

The second cake doesn’t cost enough to be worth all the calculation to get its price!! I’ll show you part of the answer, and you do the rest.

To do all this, you will need the Area (A) and Circumference (C) of both circles.

We know the diameter of the large circle is 12, so the radius is 6.

We know the diameter of the inner circle is 3, so the radius in 1.5.

The formula for the area of a circle is pi (3.14) x radius^2

A (large) = pi x 6^2 = 3.14 x 36 = 113.04 sq in

A (inner) = pi x 1.5^2 = 3.14 x 2.25 = 7.07 sq in

The formula for the circumference of a circle is pi x diameter

C (large) = pi x 12 = 37.68

C (inner) = pi x 3 = 9.42

Batter

To calculate the amount of batter, you need to find the volume of the cake.

Volume is the [A(large) – A(inner)] x depth.

Cost = Volume x price

Icing

For the icing, you need the area of the three surfaces (outside edge, inside edge, top)

[C(large) x depth] + [C(inner) x depth] + [A(large) – A(inner)]

Cost = Surface Area x price

Chocolate String

It sounds like there will be two circles of string – around the large and inner circles.

C(large) + C(inner)

Multiply that by the cost and round up to the nearest foot -- the string must be bought in foot-long lengths