Robby's BOB

For the past 2 weeks, we learned how to find surface area's and volumes of 3-dimensional (3D) objects like rectangular prisms and cubes. Here is how to find the Surface area and Volume of a Rectangular Prism:

Surface Area of a Rectangular Prism



This is a Rectangular Prism. You can see the length, width, and height from any angle, meaning it is a meaning it is a 3D object.

Surface area is "how much wrapping you need to cover the whole object". So, if you were to cover it, you much wrapping would you need in a unit of measurement (not squared).







Our new Rectangular Prism has some measurements attached to it, so we can solve the surface area and Volume.


So:
Length = 6 cm
Width = 10 cm
Height = 6 cm

There is 1 formula for finding surface area:

-It is
(Area of L side + Area of R Side) +
(Area of Top) + Area of Bottom) +
(Area of Front + Area of Back)






One important thing must be done to simplify finding the surface area. You must turn the rectangular prism into its 'Net' form, which is as follows:



Now do the equation (Since L side and R side, and Top and bottom, and Front and back have the same area, simply x2 to use less space.:

Surface Area
=(Area of L side x 2) +
(Area of Top x 2) +
(Area of Front x 2)

=(60cm² x 2) + (36cm² x 2)
+ (60cm² x 2)
=(120cm²) + (72cm²) + (120cm²)

=312cm² is the Surface Area





Now Volume is pretty easy, there are 2 different ways on finding it.
One is : Length x Width x Height
the other one is Area of Base x Height

I'll do both to prove they both work:

The measurements are:
L = 6 cm
W = 10 cm
H = 6 cm

The Formula:
= Length x Width x Height
= 6cm x 10 cm x 6 cm
= 60 cm x 6
= 360 cm³ (note, the answer is CUBED or the power of 3 (³) because you are multiplying 3 dimensions together: length, width, and height)




The Second Formula is Area of Base x Height:
Area of Base = L x W or L x H or W x H
Area of Base = L x W (for now)
Area of Base = 6cm x 10cm
Area of Base = 60cm²

Height = 6cm

60cm² x 6 = 360 cm³

See, the answer is 360cm³ for both, meaning they both work.
The Length x Width x Height one is easier, in my opinion, because it takes less work to do.
And that's how you find the volume and surface area of a Rectangular Prism.

Kierra's BoB

What was the hardest thing about this unit?
I think the hardest thing about this unit was cutting the subs with the rusty spoon and limiting the amount of cuts and trying to make it so everyone each go an equal amount of sub.

What do you understand now that you did not before?
One thing I understood that i never even knew existed before was splitting the clock into parts to help compare fractions and to tell how one was larger than the other.

What would be one thing you would teach your parents about this unit?
One thing I would teach my parents is how to compare fractions and show them the clock idea. I would also show them how to do the ratio chart and the rectangle (where you split it into half, then into another half.)

Andrea BOB

What was the hardest thing about this unit?

The hardest thing for me about this unit was the subs. It was really hard to make the pieces in each group even because they were unfriendly numbers.


What do you understand now that did not understand before?

One thing i didn't understand was dividing clocks. I didn't realize that all you had to do was divide the denominator of the fraction by 60 because that is how many minutes an equals to.


What would be the one thing you would teach your parent's about this unit.

I would teach my parent's how to divide fractions on a clock because they don't know how to do it, but my parent's are good at math, so it would be showing them another method.