1:A customer has requested a bookcase with the two shelves having a total
area of 864 square inches. What
should b equal to meet the customer's
specifications?

2: Barnard has a stain on his wall and would like to cover it up with a bookcase. What should b equal in order for the back of the bookcase to cover an area of 4800 square inches

1. 8.5 inches

2. 20 inches

Step-by-step explanation:

1. Total area of the shelve = (4b x 3b)

864 = 12

      = 12

=  

   = 72

b =

  = 8.486 inches

b = 8.5 inches

2. Bernard wish to cover an area of 4800 square inches.

Then,

Area = length x width

4800 = 4b x 3b

         = 12

=

   = 400

b =

   = 20 inches

The value of b should be 20 inches.

check the picture below.

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it