To find the measure of angle \( ADB \) in rhombus \( ABCD \), we can use the properties of rhombuses and triangles.
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In a rhombus, the opposite angles are equal, and the adjacent angles are supplementary. Since \( mA = 112^\circ \), we know: \[ mC = 112^\circ \]
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The adjacent angles \( A \) and \( B \) are supplementary: \[ mA + mB = 180^\circ \] Therefore, we can find \( mB \): \[ mB = 180^\circ - 112^\circ = 68^\circ \] Similarly, since \( mC \) and \( mD \) are also adjacent: \[ mC + mD = 180^\circ \] Thus, \[ mD = 180^\circ - 112^\circ = 68^\circ \]
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The diagonals of a rhombus bisect each other at right angles. Therefore, triangle \( ADB \) is formed by the diagonal \( DB \), where \( D \) is the bottom left vertex.
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Since diagonals bisect the angles of the rhombus, we can find \( mADB \): \[ mADB = \frac{mA}{2} = \frac{112^\circ}{2} = 56^\circ \]
So, the measure of angle \( ADB \) is: \[ mADB = 56^\circ \]