An architect has designed a floor plan for a new bedroom with 1:80 as the scale. If the length of the bedroom on the plan is 650mm, what would the actual length be in metres?
A scale is the ratio of the size of a model to the actual object it represents.
Quad boxes are used to easily find rates
First, fill up the quad boxes with the three known values and have the unknown value be x.
Plan
Actual
1
80
650
x
Next, equate the two columns and solve for x.
1650
=
80x
1(x)
=
80(650)
Cross multiply
x
=
52000
Since the given measurement for the plan is in mm, this value will be 52000mm.
Finally, convert the millimetres into metres.
1metre
=
1000millimetres
x
=
52000×11000
1000mm has 3 zeroes ∴ move 3 decimal places to left
x
=
520001000
=
52
x=52m
Question 2 of 4
2. Question
A map indicates that the distance between two towns is 20cm.
If the scale of the map is 1:10000, what is the actual distance between the two towns in kilometres?