# 15 POINTS A 4-inch length is represented as 1/8 on a scale drawing. What is the scale used on the drawing? 1 foot=3/4 inch 1 foot =3/8 inch 1 foot= 1/2 inch 1 foot = 1/4 inch Please explain im not good at scales and models.

###### Question:

1 foot=3/4 inch

1 foot =3/8 inch

1 foot= 1/2 inch

1 foot = 1/4 inch

Please explain im not good at scales and models.

## Answers

9514 1404 393Answer: (b) 1 foot = 3/8 inchStep-by-step explanation:The given ratio is ... actual : scale = 4" : 1/8"You know that 1 foot = 12 in = 3×4 in, so you can multiply the above ratio by 3 to see what it is for 1 foot. actual : scale = 3×4" : 3×1/8" = 12" : 3/8" = 1 foot : 3/8 in______Alternate approachEssentially, we're saying that the ratios between actual measures and those on a scaled drawing or model form a proportion. scale / actual = (1/8")/(4 in) = ??/(12 in)Multiplying by 12 in, we get ... ?? = (12 in)(1/8")/(4 in) = 3×1/8" ?? = 3/8"__More detailNotice that this only works when the units in the ratio (12 in)/(4 in) cancel to give a pure number 12/4 = 3.If we had put 1 foot in the proportion, then we would end up with ?? being expressed in feet, not inches: (1/8")/(4") = ??/(1 ft) ?? = (1 ft)(1/8")/(4") = (1 ft)(1/32) = 1/32 ftThen, to find the answer to the question, we would have to find out how many inches is 1/32 ft. 1/32 ft = (1/32)(12 in) = 12/32 in = 3/8 in__End commentFor best results, the units in corresponding parts of a proportion should be the same.