Deniel's surface area growing post

Okay guys here is my surface area growing post about right rectangular prism, right triangles, and cylinders

Here is my first surface area question:

Okay here is what I did:

front:

13.5 cm x 18.5cm =area 13.5 x 18.5= 249.75cm x 2 = 499.5cm

side:

5 cm x 13.5cm =area 13.5 x 5= 67.5cm x 2 = 135cm

length:

18.5 cm x 5cm =area 18.5 x 5= 92.5cm x 2= 185cm

499.5+135+185= 819.5

Area= 819.5cm

Here is my second question:

Okay so here's what I did:

A= l x w A= (b x h) / 2

A= 9 x 3 A=(3 x 2.6) / 2

A= 27 The area on one rectangle is 27m A=7.8 / 2

A=3.9 and its the area of one triangle

Surface Area= (3 x rectangle) + (2 x area of triangle)

= (3 x 27) + (2 x 3.9)

= 81 + 7.8

= 88.8

So the surface area is 88.8 centimetre squared.

Here's my third question:

Here's what I did:

Determine the radius of each circle:

7.5 / 2 = 3.75 so 3.75 is the radius of each circle

Find the area of the circle

A=π x r2

A=3.14 x 3.75 x 2

A= 44.15625 so the area of one circle is 44.15625 x 2 = 88.3125 for both circles.

Find the area of the rectangle using the circumference of the circle.

A= l x w

A=(π × d) × w

A= 3.14 × 7.5 × 11

A= 259.05

The area of the rectangle is approximately 259.05 cm2.

Calculate the total surface area.

Surface area = 88.3125 + 259.05

= 347.3625

The total surface area is approximately 347.36 cm2

So here is my surface area growing post :)