Rectangular Prism

I made this in Microsoft paint, so I gave it fake measurements if thats alright.

Net of Rectangular Prism also made in Microsoft Paint (tell me if somethings wrong because I always mess up the nets)

The formula you use to calculate the surface area of a rectangular prism is lxw (length x width). We will do this with all faces to get the area of each face, then add them together, which should give us the surface area.

5cm x 10cm = 50 cm2

5cm x 17cm = 85 cm2

10cm x 17cm = 170 cm2

50cm2+85cm2+170cm2 =

**305 cm2**

Triangular Prism

Heres is the shape

Here is the Net

The formula to calculate the surface area of a Triangular Prism is bxh÷2 (BASE X HEIGHT ÷ 2)

And heres the answer:

Rectangle = lxw

Rectangle = 2cm x 20cm

Rectangle = 40cm2

Triangle = bxh÷2

Triangle = 2cm x 5cm ÷ 2cm

Triangle = 5cm2

40cm2+5cm2 =

**45cm2**

**Please tell me if I made a mistake, because I usually mess up with Triangular Prism's.**

Now last but not least... the cylinder (-.-)

Net of a Cylinder here

Now we have the diameter, but we need to find the radius.

r = d÷2

r = 5 ÷ 2

r = 2.5cm

Now lets find the area of both circle(s)

A = pi x r x r

A = 3.14 x 2.5cm x 2.5cm

A = 19.625cm2 x 2 = 39.25cm2 (AREA OF BOTH CIRCLES)

Area of the Rectangle

A = lxw

A = (pi x d) x w

A = 3.14 x 5cm x 15cm

A = 235.50cm2

39.25cm2 + 235.50cm2 =

**274.75cm2**

## No comments:

## Post a Comment