Free · Geometry and function relationships

Angles Formed by Rectangle Diagonals

The rectangle corner angles are 90°. Its diagonals bisect one another; adjacent intersection angles add to 180°. Enter the selected labeled angle in degrees.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

For TheKnownVariable = 0, angle_a = 30, Answer1 = 30, Answer2 = 60, Answer3 = 120, Answer4 = 60.

A=B=E=F; C=D=G=H=90°−A; I=K=180°−2A

Worked example

Enter these known values and leave the other values blank.

Select the known variable
0
A
30 deg
A, B, E, F
30 deg
C, D, G, H
60 deg
I, K
120 deg
L, J
60 deg

Assumptions and limitations

  • The rectangle corner angles are 90°. Its diagonals bisect one another; adjacent intersection angles add to 180°. Enter the selected labeled angle in degrees.
  • Clear the unknown field before solving. Locks preserve known quantities; an inverse may have multiple solutions and this model selects its principal branch.
  • Numerical rounding does not describe measurement uncertainty. Extremely large arguments or near-singular inverses can exceed the available precision; use moderate values for interpretable finite results.

Common questions

How do I enter a consistent set of values?

The rectangle corner angles are 90°. Its diagonals bisect one another; adjacent intersection angles add to 180°. Enter the selected labeled angle in degrees.

Can I calculate a missing input?

Clear that field and provide enough independent known quantities. Output-only fields and nonunique inverse branches may need a different mode.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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