Math Problem Statement

In the given figure, PQ and FD are diameters of circles O. Find the indicated measures for angles and arcs.

Solution

Let's go through each question based on the diagrams and provided values.

For the first circle (with diameter PQPQ):

  1. 10. mQORm\angle QOR:

    • Since PQPQ is the diameter, angle QORQOR forms a central angle of 7575^\circ as marked in the figure.
    • Answer: mQOR=75m\angle QOR = 75^\circ.
  2. 11. m\overarcPRm\overarc{PR}:

    • Arc PRPR corresponds to the central angle QOR=75QOR = 75^\circ.
    • Answer: m\overarcPR=75m\overarc{PR} = 75^\circ.
  3. 12. m\overarcQRm\overarc{QR}:

    • Since PQPQ is the diameter, the circle is divided into two semicircles, meaning m\overarcQRm\overarc{QR} is the remaining arc.
    • To find m\overarcQRm\overarc{QR}, subtract 7575^\circ from 180180^\circ.
    • Answer: m\overarcQR=18075=105m\overarc{QR} = 180^\circ - 75^\circ = 105^\circ.
  4. 13. m\overarcPSQm\overarc{PSQ}:

    • Arc PSQPSQ represents the entire circle minus arc PRPR.
    • Answer: m\overarcPSQ=36075=285m\overarc{PSQ} = 360^\circ - 75^\circ = 285^\circ.

For the second circle (with diameter FDFD):

  1. 14. mCOFm\angle COF:

    • COFCOF forms a central angle of 4545^\circ as marked in the figure.
    • Answer: mCOF=45m\angle COF = 45^\circ.
  2. 15. m\overarcFCm\overarc{FC}:

    • Arc FCFC corresponds to the central angle COF=45COF = 45^\circ.
    • Answer: m\overarcFC=45m\overarc{FC} = 45^\circ.
  3. 16. m\overarcCDEm\overarc{CDE}:

    • To find m\overarcCDEm\overarc{CDE}, add the central angles corresponding to arcs CDCD and DEDE: 118+75=193118^\circ + 75^\circ = 193^\circ.
    • Answer: m\overarcCDE=193m\overarc{CDE} = 193^\circ.
  4. 17. m\overarcCFEm\overarc{CFE}:

    • Arc CFECFE represents the entire circle minus arc FDFD.
    • Since FDFD is a diameter, it subtends a semicircle of 180180^\circ.
    • Answer: m\overarcCFE=360180=180m\overarc{CFE} = 360^\circ - 180^\circ = 180^\circ.

Would you like further explanations on any of these steps?


Additional Related Questions

  1. How can we calculate the measure of an arc given its central angle?
  2. Why does a diameter divide a circle into two equal arcs?
  3. How would you find the measure of a minor arc versus a major arc?
  4. What properties of a circle help in calculating angle measures?
  5. How do central angles relate to the arcs they intercept?

Tip

Remember, a central angle in a circle always equals the measure of the arc it intercepts.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circles
Central Angles
Arcs

Formulas

Measure of an arc = Measure of its central angle
Sum of angles around a point = 360°
Measure of a semicircle = 180°

Theorems

Central Angle Theorem

Suitable Grade Level

Grades 8-10