Answer:
40) 105 miles (mi)
42) 3.2 centimeters (cm)
Step-by-step explanation:
First determine which part of the ratio corresponds to what. Once you have figured that out, divide by the part of the ratio that corresponds to your given part and then multiply that by the other part of the ratio to derive the quantity.
If a:b
Then a × a/b = b, and b × a/b = a.
You can think of : as "to".
For example, you are given a map with a scale ratio of 1 in : 20 mi, this means that for every inch of the map, there is an actual distance of 20 miles.
So in this situation, the left part of the ratio is the length of the map in inches, and the right part of the ratio is the real distance in miles. For x inches of the map, there is 20 x miles of actual distance. Therefore 3.5 inches has an actual distance of 3.5 × 20 miles or 105 miles of actual distance.
For problem 2, you are given a ratio of 1 m : 2 cm, this means that for every 1 meter of the drawing, there is 2 cm of the plant. Therefore if you have 1.6 meter of the map, then you have 1.6 × 2 cm of the plant or 3.2 cm. For both situations the left part of the ratio is 1 which means that you just multiply by the right part of the ratio by which you are given.
