The $m\angle B$ is $93^{\circ }$ $m\overparen {BC}$ is $58^{\circ }$ and $m\overparen {CD}$ is $106^{\circ }$ Find the missing angle measures.

(2 points)
$m\angle A=\square ^{\circ },m\angle C=\square ^{\circ }$ and $m\angle D=\square ^{\circ }$

1 answer

To find the missing angles in the scenario described, we can use the properties of triangles and the angles in polygons.

  1. We are given:

    • \(m\angle B = 93^\circ\)
    • \(m\overparen{BC} = 58^\circ\)
    • \(m\overparen{CD} = 106^\circ\)

    We need to find \(m\angle A\), \(m\angle C\), and \(m\angle D\).

  2. Assuming points A, B, C, D form a closed figure (e.g., a polygon), we can analyze their relationships:

    • The sum of the angles in any quadrilateral is \(360^\circ\).
    • If \( \angle A\), \( \angle B\), \( \angle C\), and \( \angle D\) are the angles of a quadrilateral, then: \[ m\angle A + m\angle B + m\angle C + m\angle D = 360^\circ. \]
  3. We can solve step by step:

    • From our problem, we already have \(m\angle B = 93^\circ\).
    • We need to clarify what \(m\angle C\) and \(m\angle D\) are in relation to the segments \(BC\) and \(CD\).
  4. If \(m\overparen{BC}\) and \(m\overparen{CD}\) indicate the supplementary angles formed at those points (assuming we're forming triangles):

    • Let's say \(m\angle C\) is the interior angle facing \(BC\), then it is supplementary to it.

    • Therefore, \(m\angle C + m\overparen{BC} = 180^\circ\): \[ m\angle C + 58^\circ = 180^\circ \implies m\angle C = 180^\circ - 58^\circ = 122^\circ. \]

    • Similarly, for \(m\angle D\), where it is complementary with \(m\overparen{CD}\): \[ m\angle D + m\overparen{CD} = 180^\circ \implies m\angle D + 106^\circ = 180^\circ \implies m\angle D = 180^\circ - 106^\circ = 74^\circ. \]

  5. Finally, we can find \(m\angle A\) as follows: \[ m\angle A + 93^\circ + 122^\circ + 74^\circ = 360^\circ. \]

    • Adding the known angles: \[ 93^\circ + 122^\circ + 74^\circ = 289^\circ. \]
    • So, we solve for \(m\angle A\): \[ m\angle A + 289^\circ = 360^\circ \implies m\angle A = 360^\circ - 289^\circ = 71^\circ. \]

Thus, summarizing the measures:

  • \(m\angle A = 71^\circ\)
  • \(m\angle C = 122^\circ\)
  • \(m\angle D = 74^\circ\)

Final answers: \(m\angle A = \boxed{71^\circ}, m\angle C = \boxed{122^\circ}, m\angle D = \boxed{74^\circ}\).