Circles

• What is the formula for the radius in terms of diameter?

  r = ½D
• What is the formula for the area of a circle?

  A = πr²
• How is diameter related to radius?

  D = 2r
• What is the formula for the circumference of a circle?

  C = πD
• How is arc length calculated?

  Arc length = centre angle / 360° x πD
• What is the formula for the area of a sector?

  sector = centre angle x πr² / 360°
• What does "bisect" mean in geometry?

  • Split in 2
• What are the properties of a line that bisects a chord?

  1. Splits chord into 2 equal halves
  2. Makes right angle with chord
  3. Passes through circle center
• What is the definition of a minor segment in a circle?

  A minor segment is part of a circle.
• What does the Pythagorean theorem state?

  a² + b² = c²
• What does SOHCAHTOA represent?

  It represents trigonometric ratios.
• What is the angle of a semicircle?

  90°
• What is a chord in a circle?

  A line segment between two points on a circle.
• What is the definition of a radius?

  A line segment from the center to the circle's edge.
• What is a sector in a circle?

  A region bounded by two radii and an arc.
• What is a tangent in relation to a circle?

  A line that touches the outside of a circle.
• What angle does a tangent make with the radius at the point of contact?

  90° angle