1. A timber fence is to be built on sloping land, with the shortest piece of timber 1.2m and the longest 1.8m. There are 61 pieces of timber in the fence.
a) what is the difference in height between each piece of timber?
b) What length of timber is needed for the fence altogether?
2007-07-22 21:44:18 · 3 answers · asked by loza 2 in Science & Mathematics ➔ Mathematics
tn=a+(n-1)d
1.8=1.2+60d
d=.001m=1mm
this is d difference in length
sum=n/2(a+tn)
=61/2*3
=91.5m
2007-07-22 21:54:03 · answer #1 · answered by Anonymous · 1⤊ 0⤋
General Equation:
Ad = Ao + d(n-1)
A61 = 1.2 +d(61-1)
1.8 = 1.2 + d(61-1)
d = .01 meters
S = [(n)(Ao + An)]/2
= [61(1.2+1.8)]/2
= 91.5 meters
2007-07-22 21:56:40 · answer #2 · answered by rene rhey j 2 · 0⤊ 1⤋
a)
(1.8 - 1.2)/60 = 0.6/60 = 0.01 m = 1 cm
b)
0.01(60)(61)/2 + 61*1.2 =
61(1.2 + 0.3) = 61*1.5 = 91.5 m
2007-07-22 22:02:52 · answer #3 · answered by Helmut 7 · 0⤊ 1⤋