The Triple beam balance is a typical mechanical balance.
It has a beam which is supported by a fulcrum. On one side is a pan on which the object is placed. On the other side, the beam is split into three parallel beams , each supporting one weight. In measuring the weight of an object, rather than adding additional weights, each of the three weights can be slid along the beam to increase their lever arm.
It works just like a tetter-totter. If you have two people of unequal weight, the heavier person sits closer to the fulcrum to decrease their lever arm.
How to read scale of triple beam balance?
a balance needs to be zeroed out. that means all of the weights need to be moved to the left side of the beams.
1.Read a hundreds first.
2.Read tens second.
3.Read the units.
4.Add all hundreds,tens and units.
from this sample the hundreds is 90g, tens is 30g and units is 8g. So answer is 90+30+8=128g.