Carpentry Joinery Phase 4 Maths Ratio Proportion Sample

π Carpentry & Joinery Phase 4 Maths Ratio & Proportion Sample Questions & Solutions

Carpentry & Joinery Phase 4 Maths Ratio & Proportion • A pitched roof is constructed with a pitch of 1 : 3 rise to span ratio. If the span of the roof is 4. 8 m, what is its rise • 4. 8 is = 3 parts so 4. 8 ÷ 3 = 1. 6 or 1 part • 1. 6 m = rise • Or the rise is = 1/3 of the span = 1. 6 m rise? 4. 8 m

Carpentry & Joinery Phase 4 Maths Ratio & Proportion • Flat roofs have a fall that does not exceed 1 : 6 ratio of rise to run of falling surface ( 10° pitch approx. ) • e. g. A flat roof extends from the rear wall of a house over an extension that is 4. 2 m further out. Calculate the rise given a ratio of 1 : 9 • 4. 2 ÷ 9 = 0. 46 m • = 460 mm rise Answer

Carpentry & Joinery Phase 4 Maths Ratio & Proportion • The recommended fall for 100 mm PVC drainage pipe from a domestic dwelling is 1 : 40 • On a run of 7. 685 m of 100 mm waste pipe, by how much will the pipe fall from highest to lowest point assuming a 1 : 40 gradient? • 7. 685 ÷ 40 = 0. 192125 = 192 mm Answer

Carpentry & Joinery Phase 4 Maths Ratio & Proportion • If the cost of a carpentry project came to a total of € 7, 850, calculate the cost of each item listed when the ratio is as follows: 1. Materials cost 2/5 2. Labour costs 3/10 3. Profit cost 1/10 4. VAT cost 1/5

Carpentry & Joinery Phase 4 Maths Ratio & Proportion • Firstly, convert all fractions to the same denominator i. e. 2/5 to 4/10 & 1/5 to 2/10 • Now we can divide our total by the denominator (10) so 7, 850 ÷ 10 = 785 • Material = 2/5 = 4/10 = 4 x 785 = € 3, 140 • Labour = 3/10 = 3 x 785 = € 2, 355 • Profit = 1/10 = 1 x 785 = € 785 • VAT = 1/5 = 2/10 = 2 x 785 = € 1, 570 • 3, 140 + 2, 355 + 785 + 1, 570 = € 7, 850