Maths Question

Question

On a scale drawing, the scale is 1/18.  A basketball backboard system is 6 inches tall on the

drawing. What is the height of the actual basketball system.

 

 

1.  36 inches or 3 ft

 

2.  240 inches or 20 ft

 

3.  108 inches or 9 ft

 

4.  96 inches or 8ft 

Answer 1

A scale of "1:18" means that you see 1 inch for what is really 18 inches.  So, you see 6 inches for what is actually x inches tall.  Let's find x.

 

   1/18 = 6/x       "1 is to 18 as 6 is to x"

    x/18 = 6         [multiply both sides by x]

    x = 108 inches       [multiply both sides by 18;

                note: to do both multiplications at once, cross-multiply]

 

To convert units without changing the value, we use the multiplicative identity (that is, 1).  For this problem,

      1  =   (1 foot) / (12 inches)

 

     108 inches

     (108 inches) * 1

     (108 inches) * ( (1 foot) / (12 inches) )

       9 feet

Answer 2

What you need to do is think that the drawing is 1:18 scale or 1/18.  For every inch the actual figure is 18x larger. Or 18 times 6 inches = 108 inches or 9 ft.    Try 3. 108 inches or 9 ft.