Danny is painting a doghouse to make it durable he will paint all sides including the bottom the dog house is shaped like a rectangular prism with a triangular prism on top as shown how many cans of paint does Danny need to cover the doghouse if each can covers 20ft squared

Respuesta :

Answer:

15 cans

Step-by-step explanation:

There are two shapes that make up the dog house, they are the triangular and rectangular prism, with the combination of a semi-circle and rectangle as the door opening.

The area of a rectangle for the top ( T ) and bottom ( B ) side view:

top height = 3ft, and width= 8ft

bottom height = 4.5ft, width= 8 ft

Area ( T ) = 3 X 8 = 24 ft^2

Area ( B ) = 4.5 X 8 = 36ft^2

The front and back view is a triangle and rectangle:

area of triangle = 1/2 x base x height

with the base = 4ft,   and  sides= 3 ft

height = sqrt( side^2 - (1/2 height)^2 )^0.5

          = sqrt( 9 - 4 )  = 2.235

area of triangle( front and back )  = 1/2( 4 x 2.235 ) = 4.47 ft^2

area of rectangle ( back ) = 4 x 4.5 = 18ft

The entrance is a rectangle with area = 2.5 x 2 = 5ft^2

and semi-circle with area = (πr^2)/2 = (3.14 x 1^2)/2 = 1.57ft^2

area of entrance = 5 + 1.57 = 6.57ft^2

area of front view = 18 - 6.57 = 11.43ft^2

the total area of the doghouse is = 11.43 + 18 + 72 + 48 + 8.94  = 158.37ft^2

this is for just the outside. to get the total for inside and outside:

      158.37 x 2 = 316.74ft^2

total area per paint can = 20ft^2

total number of cans needed = 316.74 / 20  = 15 paint cans

Answer:

6 cans are needed to paint the dog house.

Step-by-step explanation: