00:01
In question 19, we're going to be considering a case where an architect is designing a covered bridge to be placed over a ravine.
00:10
And the diagram that we have here shows bf, segment bf and segment bg as the sides of the ravine and segment fg represents the road surface of the bridge, while ac represents the roof covering the bridge.
00:31
So the question is, would these measurements ensure that the roof is parallel to the road surface? so the roof here is ac and the road surface is fg.
00:53
So we want to see whether these two would be parallel given these measurements.
00:57
Now, given the measurements, for fg to be parallel to ac, we require that af is proportional to fb or cg is proportional to gf.
01:16
In other words, we want these ratios to apply.
01:20
The ratios are af over fb should be the same as cg over g over g.
01:32
In other words, f and, let me just mark this up, f and g divide ab and c b proportionally.
01:46
So let's substitute the values and see whether this equation holds.
01:50
So af is 14, fb is 35, it should be the same as cg, which is 10, and gb which is 30...