Inscribed angles and inscribed quadrilaterals
Grade 10 Math Worksheet

Circle the best answer, or write your answer on the line.
Bo stands on the edge of a round pond. Points C, D and F lie on circle O, and ∠CDF = 37°. What is the measure of arc CF?
Esme looks across a round pizza from its crust. Points C, D and F lie on circle O, and ∠CDF = 66°. What is the measure of arc CF?
Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 66°. Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 66°. O C F D 66° Not to scale Jun draws two lines from a point on a clock's rim. Points C, D and F lie on circle O, and ∠CDF = 48°. What is the measure of arc CF?
Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 48°. Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 48°. O C F D 48° Not to scale Kira draws two lines from a point on a drum's rim. Points C, D and F lie on circle O, and ∠CDF = 81°. What is the measure of arc CF?
Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 81°. Circle sketch, not to scale: center O; C, D, F on the circle; ∠CDF opens onto arc CF; ∠CDF = 81°. O C F D 81° Not to scale Luz builds a window frame inside a round opening. Quadrilateral CDFG is inscribed in circle O, with ∠C = (2x + 10)° and ∠F = (3x + 20)°. What is x?
Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (2x + 10)°, ∠F = (3x + 20)°, opposite. Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (2x + 10)°, ∠F = (3x + 20)°, opposite. O C D F G (2x + 10)° (3x + 20)° Not to scale Milo joins four points on a clock face. Quadrilateral CDFG is inscribed in circle O, with ∠C = (4x − 6)° and ∠F = (x + 21)°. What is x?
Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (4x − 6)°, ∠F = (x + 21)°, opposite. Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (4x − 6)°, ∠F = (x + 21)°, opposite. O C D F G (4x − 6)° (x + 21)° Not to scale Pia sews a four-sided patch on a round rug. Quadrilateral CDFG is inscribed in circle O, with ∠C = (5x)° and ∠F = (x + 30)°. What is x?
Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (5x)°, ∠F = (x + 30)°, opposite. Circle sketch, not to scale: center O; quadrilateral CDFG on the circle; ∠C = (5x)°, ∠F = (x + 30)°, opposite. O C D F G (5x)° (x + 30)° Not to scale Ren looks across a round pond from two spots on its edge. On circle O, ∠CDF = (3x + 5)° and ∠CGF = (x + 25)°; both open onto arc CF. What is x?
Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (3x + 5)°, ∠CGF = (x + 25)°. Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (3x + 5)°, ∠CGF = (x + 25)°. O C F D G (3x + 5)° (x + 25)° Not to scale Zee draws two angles on a clock face. On circle O, ∠CDF = (5x + 2)° and ∠CGF = (3x + 18)°; both open onto arc CF. What is x?
Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (5x + 2)°, ∠CGF = (3x + 18)°. Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (5x + 2)°, ∠CGF = (3x + 18)°. O C F D G (5x + 2)° (3x + 18)° Not to scale Ari paints two angles on a drum top. On circle O, ∠CDF = (6x − 5)° and ∠CGF = (4x + 9)°; both open onto arc CF. What is x?
Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (6x − 5)°, ∠CGF = (4x + 9)°. Circle sketch, not to scale: center O; C, F, D, G on the circle, D and G on the same side of chord CF; ∠CDF = (6x − 5)°, ∠CGF = (4x + 9)°. O C F D G (6x − 5)° (4x + 9)° Not to scale