Measures and Mensuration

Measures and Mensuration

1. Converting units

   • 1cm=10mm 1m=100cm=1000mm 1km=1000m=100000cm=1000000mm

2. Arcs, sectors, tangents and radii

   • Arc of a circle= Use the angle and compare it with 360. For instance, if the angle is 144 then it is 144/360. 144/360 = 4/5 so the arc is 4/5 of the circumferance. The work out what is 4/5 of the circumferance. (u have to work out the circumferance first)
   • Sector of a circle= This is a bit like the arc. angle/360 x
   • A tangent is a line that just touches a circle. It is always at right angles to the circles radius
   • We know a triangle is simaler if; the three sides are in the same proportion, two sides are in proportion and the angle is equal, all the angles are equal

3. Volume

   • Volume of a prism = area of cross section times length
   • Volume of a cylinder = area of front circle times length