Session 19 – Measures GCSE Maths

Length - cm, metres, km, inch, feet, miles Mass (weight) - kg, pounds, ounces Capacity (volume) – litres, gallons cm3

Metric units Kilo… Centi… Milli…. When converting between metric unit we multiply or divide by 10, 100 or 1000

Converting area and volume How many cm3 in 1m3? Ex31.1 Q 7, 8, 11, 16 and 19

Estimation using ‘common sense’ The degree of accuracy is determined by what we ae measuring. Heights of mountains are not measured to the nearest mm, or even nearest cm. Time in the Olympics is recorded to 1/100 of a second EX31.2 Q 1 and 6 through discussion

Imperial measures 1 foot = 12 inch 1 yard = 3 feet 1 pound = 16 ounces 14 pounds = 1 stone 1 gallon = 8 pints

Conversions to remember (approximate) 1 mile = 1.6 km (8/5 = 1.6) (km is shorter) 1 inch = 2.54 cm 1 foot = 30 cm (think of a ruler) 1kg = 2.2 pounds 1 pint = 568ml or 1l = 1.75 pints 1 gallon = 4.5l Ex31.3 – 10 mins

Discrete and continuous data Continuous data is measured and can take any value (it depends on the degree of accuracy you measure to) Discrete data only takes certain values. eg the number of people or a shoe size or ice skating score

Upper and lower bounds If continuous measure (c) is recorded to the nearest x then the limits of possible values for c are: C± 1 2 𝑥 For example 18cm (recorded to the nearest cm) Lies between 17.5cm and 18.5cm Although it could never be 18.5cm, but it could be 18.4999999999999999999999999999999cm

Calculating using upper and lower bounds Example page 333 Try a few from 31.5

Dimensions Length, area, volume how many dimensions If a b and c all represent length, they can all be replaced by L Length – 1 dimension = L Area - 2 dimensions = L2 Volume - 3 dimensions = L3 Any formula that cannot be simplified down to one of these can be called ‘inconsistent’ as it does not represent length, area or volume (see example d page 335)

Any time at the end go through BKSB Encourage everyone to begin their revision of topics covered

Homework Use BKSB to revise topics Produce a revision page for the geometry ‘what you need to knows’ Including 2D shapes, 3D shapes and circles