ABCD rhombus.
Calculate the size
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ABCD rhombus.
Calculate the size
According to the properties of a quadrilateral, each pair of opposite angles are equal to each other.
Therefore:
Additionally, we know that the sum of the angles in a quadrilateral equals 360 degrees.
Therefore, we can calculate angles A and D as follows:
Angle A is equal to 100.
100
Look at the angles shown in the figure below.
What is their relationship?
\( \)
Not always! A square is a special type of rhombus where all angles are 90°. But most rhombuses have different angle measures - they just need opposite angles equal and consecutive angles supplementary.
Because a rhombus is a parallelogram! In any parallelogram, consecutive angles are supplementary (add to 180°). This is a fundamental property you can always rely on.
Think of it like corners of a rectangle! Angle A is opposite to angle C, and angle B is opposite to angle D. They're diagonally across from each other.
The method stays the same! If you know any angle in a rhombus, you can find all others using:
Yes! You could use the fact that all four angles sum to 360°. Since opposite angles are equal: 2A + 2B = 360°, so 2A + 2(80°) = 360°, giving A = 100°.
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