Triangle LMN is inscribed inside a circle with diameter LM ; the inscribed angle is N . The angle measure at the vertex L is 37°. Using what you understand about inscribed angles, find the arc measure of MN .(1 point)

Responses

53°
53°

90°
90°

106°
106°

74°

1 answer

In a circle, an inscribed angle is half the measure of the arc that it intercepts. In triangle LMN, the inscribed angle at vertex N (which is the angle °) intercepts arc MN.

We are given:

  • The measure of angle L is 37°.

Since LM is the diameter, according to the inscribed angle theorem, angle N, which is opposite to diameter LM, measures 90° (as it subtends the semicircle).

Now, we can set up the relationship:

  • The inscribed angle N intercepts arc MN, and we need to find its measure.

The measure of angle N can be calculated as:

  • \( m \angle N = m \text{arc } MN / 2 \)

Since angle N is a right angle (90°):

  • \( 90° = m \text{arc } MN / 2 \)

To find the measure of arc MN, we can multiply both sides by 2:

  • \( m \text{arc } MN = 90° \times 2 = 180° \)

Next, we know that angles around point L must also take into consideration angle L which measures 37° and angle M as part of the triangle summing up to:

  • 180° (the total angle sum in triangle LMN).

Thus,

  • \( m \angle L + m \angle M + m \angle N = 180° \)
  • \( 37° + m \angle M + 90° = 180° \)

Solving for \( m \angle M \):

  • \( m \angle M = 180° - 127° = 53° \)

Now the arc measure for MN corresponds to the opposite angle measure from arc LM which equals twice \( m \angle M\):

  • \( m \text{arc } MN = 2 \times 53° = 106°\)

Thus the correct answer:

106°