Trident Help

Natural Scientific 991 manual · Chapter 16 of 18

Ratios and proportions

Find the missing number in a proportion A:B = X:D or A:B = C:X.

16.1Solve a proportion#

Press MENU, press hyp (the key with the red C legend) to open Ratio. Choose 1 for A:B = X:D (find the first term of the second ratio) or 2 for A:B = C:X (find the last term). Type the three known numbers, pressing = after each.

Example 16.1

2 : 3 = X : 9

  1. Ratio, type 1, then A = 2, B = 3, D = 9.

    MENUhyp12=3=9=
Result of the example "2 : 3 = X : 9" The display shows: X=6.
You should seeX=6
Example 16.2

2 : 3 = 4 : X

  1. Ratio, type 2, then A = 2, B = 3, C = 4.

    MENUhyp22=3=4=
Result of the example "2 : 3 = 4 : X" The display shows: X=6.
You should seeX=6
AB=XD⇒X=ADB\frac{A}{B}=\frac{X}{D}\Rightarrow X=\frac{AD}{B}
Solving a proportion

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