LMNO is a parallelogram, with $\angle M = (11x)^{\circ}$ and $\angle N = (6x - 7)^{\circ}$. Which statements are true about parallelogram LMNO? Choose three correct answers.



$x = 11$

$m\angle O = 121^{\circ}$

$m\angle L = 22^{\circ}$

$m\angle M = 111^{\circ}$

Verified Answer :

  • Solve for \(x\) using the property that consecutive angles in a parallelogram are supplementary: \(11x + (6x - 7) = 180 \Rightarrow x = 11\).
  • Calculate the angle measures using \(x=11\): \(m\angle M = 121^{\circ}\), \(m\angle N = 59^{\circ}\), \(m\angle O = 121^{\circ}\), and \(m\angle L = 59^{\circ}\).
  • Evaluate the given statements: \(x = 11\) (True), \(m\angle O = 121^{\circ}\) (True), \(m\angle L = 22^{\circ}\) (False), \(m\angle M = 111^{\circ}\) (False).
  • Final correct statements: \(\boxed{a, b}\).

Explanation

  1. Solve for the value of x.

In a parallelogram \(LMNO\), consecutive angles are supplementary, meaning their sum is \(180^{\circ}\). We are given:

  • \(\angle M = (11x)^{\circ}\)
  • \(\angle N = (6x - 7)^{\circ}\)

Since \(\angle M\) and \(\angle N\) are consecutive, we have:
\(\angle M + \angle N = 180^{\circ}\)
\((11x) + (6x - 7) = 180\)
\(17x - 7 = 180\)
\(17x = 187\)
\(x = 11\)

Thus, the value of \(x\) is \(11\). This confirms that statement a is true.

  1. Calculate the measures of the angles and evaluate the statements.

Using the value \(x = 11\), we calculate the measures of the angles:

  • \(m\angle M = 11(11)^{\circ} = 121^{\circ}\)
  • \(m\angle N = 6(11) - 7 = 66 - 7 = 59^{\circ}\)

In a parallelogram, opposite angles are equal. Therefore:

  • \(m\angle O = m\angle M = 121^{\circ}\)
  • \(m\angle L = m\angle N = 59^{\circ}\)

Comparing these to the given options:

  • a. \(x = 11\) is True.
  • b. \(m\angle O = 121^{\circ}\) is True.
  • c. \(m\angle L = 22^{\circ}\) is False (it is \(59^{\circ}\)).
  • d. \(m\angle M = 111^{\circ}\) is False (it is \(121^{\circ}\)).

Note: Since the prompt asks for three correct answers but only two appear to be true based on standard geometry, we will list the true statements derived from our calculations.

Examples

When designing a structural frame for a building, engineers often use properties of parallelograms to ensure stability. For instance, if a wall frame is shaped as a parallelogram and the angle of one corner is known to be \(121^{\circ}\), they can instantly determine that the adjacent angle must be \(59^{\circ}\) to keep the structure aligned. These geometric relationships ensure that every beam is cut to the correct angle, maintaining the integrity and symmetry of the entire building.