1.4 Circular measure

2 of 2 objectives have lessons · 0 studied · 0 secure

Lessons

Radians, the circle's own unitDefine the radian, convert between radians and degrees, and know the key angles (π/6, π/4, π/3, π/2, π…) by heart. 6 min, not started
Arc length and sector areaUse s = rθ and A = ½r²θ (θ in radians) to find arc lengths, sector areas and perimeters, and work backwards to find r or θ. 5 min, not started
Chords, triangles and segmentsFind the area of triangle OAB with ½r² sin θ, the chord length with 2r sin(θ/2), and the area and perimeter of a segment. 8 min, not started
Shaded regions with tangents and trianglesFind angles and lengths in the triangles that come with circle diagrams (tangents, chords, radii), then add and subtract areas to find shaded regions. 8 min, not started

2 objectives

What Cambridge says you should be able to do, in our words. Codes are the topic number plus the objective’s position.

1.4.1

Understand the definition of a radian, and use the relationship between radians and degrees.

Taught in: Radians, the circle's own unit · 7 questions

1.4.2

Use the formulae s = rθ and A = ½r²θ in solving problems about the arc length and sector area of a circle.

Includes calculating lengths and angles in triangles and areas of triangles.

Taught in: Arc length and sector area, Chords, triangles and segments, Shaded regions with tangents and triangles · 20 questions