Nolan Piper - Ratios
Ratios express relationships between things, and are useful when it is assumed that the relationship can be extended. This is often a valid assumption, but it requires verification. (For example, if I can eat one apple in 5 minutes, it does not follow that I can eat 96 apples in 8 hours). There are countless situations, however, where ratios are applicable and where proportional comparisons can be made, and this software application is built to solve these problems easy.
The first common type of problem presents two proportional ratios, but with an unknown.
Solve - Examples:
1) An 8” x 10” portrait needs to be scaled to a height of 6.5”
What is the resulting width?
2) Similar triangles:
A 3:4:5 triangle is scaled up for a project. The new height is 46. What are the other lengths?
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3)A 48” long steel bar weighs 30 pounds. A worker cuts off an 8” piece. How much does it weigh?
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4)If a dog needs 2 tablets per 15 pounds and weighs 53 pounds, how many tablets are needed?
Solve - Setting up the problem:
It is important to set it up the problem so that the following concept is true:
Initially the large green button steps through “Units” options. In ratio problems, units can be almost anything -- what is important is that the concept above (A is to B as C is to D) is true. After getting familiar with the application, the “arrows” units choice may be a favorite. The displayed units are intended to make the ratio relationships clear; the choice of units does not affect the calculations in any way.
Always start with the known ratio on the left (in the gray boxes). Then enter the known “C” or “D” in one of the boxes on the right and leave the unknown box blank. Next, press the large green “Solve” button. Look at the calculated result and be sure that it makes sense.
The proportion and visualizer bars illustrate the ratio in the space below the gray boxes for reference. In the tablet quantity problem shown below, the base ratio is the equivalent of approximately 0.133 tablets per pound.
Comments Widget
Application Guide:
A =3
C = 5
B = 4
a = 46
c = ?
b = ?
A
a
B
b
=
A
a
B
b
C
c
=
=
10
8
6.5
?
10
8
6.5
?
=
10 is to 8 as 6.5 is to ?
3
46
4
b
=
A
a
C
c
=
3
46
5
c
=
48
30
8
?
=
3 is to 46 as 4 is to ?
48 is to 30 as 8 is to ?
3 is to 46 as 5 is to ?
2
15
?
53
=
2 is to 15 as ? is to 53
A
B
C
D
=
A is to B as C is to D
