uwotm8
New Member
Basically this is in a 2009 gen trial paper. The answer is C but no explanation is given.
Unless there's a fuckup, I can't wrap my head around it.
If anyone could explain it, it would be greatly appreciated.
I summon thee, Math gods please explain this (general) question. (1 Viewer)
- Thread starter uwotm8
- Start date
Basically this is in a 2009 gen trial paper. The answer is C but no explanation is given.
Unless there's a fuckup, I can't wrap my head around it.
If anyone could explain it, it would be greatly appreciated.
aDimitri
i'm the cook
answers are wrong, should be 200/3 (66.66)
Cleavage
Clarence
- Joined
- Sep 1, 2013
- Messages
- 563
- Gender
- Male
- HSC
- 2014
- Uni Grad
- 2018
is that because the area of the top triangle is equal to a third of the area of the trapezium?
Consider the top two triangles as one.
The ratio of the side lengths of this triangle and the larger (all-encompassing) triangle is 5:10 = 1:2
So the ratio of their areas is 1:4
ie. the smaller triangle is 1/4 of the total area
So the trapezium (the 'left-over') is 3/4 of the total area.
So the total area is 4/3 of the area of the trapezium, which is 66.666... as previously stated.
The ratio of the side lengths of this triangle and the larger (all-encompassing) triangle is 5:10 = 1:2
So the ratio of their areas is 1:4
ie. the smaller triangle is 1/4 of the total area
So the trapezium (the 'left-over') is 3/4 of the total area.
So the total area is 4/3 of the area of the trapezium, which is 66.666... as previously stated.