Question

The scale factor on a scale drawing of machine part is 15 1 /8. If the part is 3 7/8 inches long as the drawing, how long is the actual part?

A)3 28/31 inches
B)11 1/4 inches
C)19inches
D) 58 39/64 inches​

Answer 1

Option D) 58 39/64 inches​

Explanation:

we know that

The scale drawing is

`15(1)/(8)`

convert to an improper fraction

`15(1)/(8)=(15*8+1)/(8)=(121)/(8)`

That means

121 in in the actual, represent 8 in on a scale drawing

To find how long is the actual part for 3 7/8 inches long as the drawing

Apply proportion

First convert to an improper fraction

`3(7)/(8)=(3*8+7)/(8)=(31)/(8)`

`(121)/(8)(actual)/(drawing) =(x)/((31/8))(actual)/(drawing)\\ \\x=121(31/8)/8\\ \\x=(3,751)/(64)\ in`

convert to mixed number

`(3,751)/(64)\ in=(3,712)/(64) +(39)/(64) =58(39)/(64)\ in`