Ratio Calculations
The RATIO Mode lets you determine the value of X in the ratio expression a : b = X : d (or a : b = c : X) when the values of a, b, c and d are known. The following shows the general procedure for using RATIO.
1. Press 
(RATIO) to enter the RATIO Mode.
2. On the menu that appears, select 
(a:b=X:d) or 
(a:b=c:X).
3. On the Coefficient Editor screen that appears, input up to 10 digits for each of the required values (a, b, c, d).
To solve 3 : 8 = X : 12 for X, for example, press in step 1, and then input the following for the coefficients (a = 3, b = 8, d = 12):3
812.
To change a coefficient value you already have input, move the cursor to the appropriate cell, input the new value, and then press .
Pressing 
will clear all of the coefficients to zero.
Note: The following operations are not supported by the Coefficient Editor: 
, 
(M-), 
(STO). Pol, Rec, ÷R, and multi-statements also cannot be input with the Coefficient Editor.
4. After all the values are the way you want, press .
This displays the solution (value of X).
Pressing again will return to the Coefficient Editor.
Important!
A Math ERROR will occur if you perform a calculation while 0 is input for a coefficient.
Changing the Ratio Expression Type
Re-enter the RATIO Mode and select the ratio expression type you want from the menu that appears. Changing the ratio expression type causes the values of all Coefficient Editor coefficients to change to zero.
RATIO Mode Calculation Example
Example 1: To calculate X in the ratio 1 : 2 = X : 10
(RATIO)(a:b=X:d)
1210
Example 2: To calculate X in the ratio 1 : 2 = 10 : X
- (RATIO)(a:b=c:X)
1210
