Two angles of a quadrilateral measure 300° and 28°. The other two angles are in a ratio of 7:9. What are the measures of those two angles?

° and
°

1 answer

To find the measures of the two unknown angles in the quadrilateral, we first need to use the fact that the sum of the angles in any quadrilateral is \(360^\circ\).

Given:

  • The first two angles measure \(300^\circ\) and \(28^\circ\).
  • Let the two unknown angles be \(x\) and \(y\), with the given ratio \(x:y = 7:9\).
  1. First, calculate the sum of the known angles: \[ 300^\circ + 28^\circ = 328^\circ \]

  2. Calculate the sum of the unknown angles: \[ x + y = 360^\circ - 328^\circ = 32^\circ \]

  3. Since \(x\) and \(y\) are in the ratio \(7:9\), we can express them in terms of a variable \(k\): \[ x = 7k \quad \text{and} \quad y = 9k \]

  4. Substitute these expressions into the equation for the sum of the angles: \[ 7k + 9k = 32^\circ \] \[ 16k = 32^\circ \] \[ k = 2^\circ \]

  5. Now, substitute \(k = 2^\circ\) back into the expressions for \(x\) and \(y\): \[ x = 7k = 7 \times 2^\circ = 14^\circ \] \[ y = 9k = 9 \times 2^\circ = 18^\circ \]

Thus, the measures of the two unknown angles are: \[ \text{First angle: } 14^\circ \] \[ \text{Second angle: } 18^\circ \]

Final answer: 14° and 18°