Find a square root
Get the square root of a number, exactly or as a decimal.
The square root of a number is the value that gives the number when multiplied by itself. The square root of 144 is 12 because 12 × 12 = 144.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Press 2nd, then the x² key to get the √( symbol. Type 144 and close the bracket.
2nd√x²144)Press enter.
enter
You should see√(144) 12
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Press the square-root key and type 2. The calculator keeps it exact.
√2=Press S⇔D to see the decimal value.
S⇔D
You should see√2 1.414213562
Classic CAS
Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.
Press ctrl then the x² key for the square-root symbol. Type 8 and press enter. The answer is simplified.
ctrl√x²8enter
You should see√8 2·√2
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Key in 2 and press the √x key.
2√x
You should see1.4142
RPN Power 48
Start on the main screen: Press ON to cancel what you are typing, then use the stack view. Open the MODE or VAR menu any time; the stack is always shown above the menu row.
Type 49, then press the square-root key. The result replaces the number on the stack.
49√x
You should see1: 7
Tips
- You cannot take the square root of a negative number in real mode. Use the complex-number guide for that.