Flashcards
Arc length and Sector area
Cards in this deck (10)
- 1Define 1 radianThe size of the angle formed at the centre of a circle by 2 radii which join the ends of an arc equal in length to the radius
- 2π^c (π radians) is equal to how many degrees?180 degrees
- 3How do we calculate arc length?l = rθ
- 4How do we calculate sector area?A = 0.5 r^2 θ
- 5What is the sine rule for angle / length?a/sinA = b/sinB = c/sinC
- 6What is the cosine rule?a^2 = b^2 + c^2 - 2bcCosA
OR
cosA = (b^2 + c^2 - a^2) / 2bc - 7What is the sine rule for area?A = 0.5 ab sinC
- 8What is the area of a triangle?1/2 b x h
- 9—0.5 (8)^2 (0.430) = 13.76cm^2
20 - 13.76 = 6.24cm^2 (area)
8 x 0.430 = 3.44cm (length) - 10IMPORTANT NOTE:Ensure when working with trigonometric functions that your calculator is in radians when working with arc lengths and sector areas!