Finding the Area of a Triangle  TOPIC_SOLVED

Geometric formulae, word problems, theorems and proofs, etc.

Finding the Area of a Triangle

Postby cruxxfay on Tue Aug 14, 2012 11:00 am

Image

Thank you for your time, I just need some guidance/hints on this. It is a right angled triangle with the height being 3.7 cm and a length of the base being 3.5 cm. I tried to construct another triangle on top of the 3.5 cm length in an attempt to find the base length and failed. Not quite sure where to start.
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Postby stapel_eliz on Tue Aug 14, 2012 12:18 pm

cruxxfay wrote:Image

Thank you for your time, I just need some guidance/hints on this. It is a right angled triangle with the height being 3.7 cm and a length of the base being 3.5 cm. I tried to construct another triangle on top of the 3.5 cm length in an attempt to find the base length and failed. Not quite sure where to start.

As posted, the base of the right triangle is not given; the picture shows the base of the secondary triangle, the one "attached" to the right of the right triangle, as being 3.5 cm.

Please provide the exact text of (or graphic for?) the exercise. Thank you! :wink:
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Re: Finding the Area of a Triangle

Postby cruxxfay on Wed Aug 15, 2012 3:25 am

The question is:

"Find the areas of these shapes. Give your answer to 3 significant figures."

There are 6 shapes in that exercise and this particular one is question 5.

Graphically I am given 3 information, as you have already noticed.

I am starting to wonder if they are missing one piece of information or is it that I am just lost.

Yes the entire base is not given, only a length of it is 3.5 m.

Thanks.
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  TOPIC_SOLVED

Postby stapel_eliz on Wed Aug 15, 2012 12:02 pm

cruxxfay wrote:Graphically I am given 3 information, as you have already noticed.

I am starting to wonder if they are missing one piece of information or is it that I am just lost.

Imagine (in your head) that the figure is stretchy. Picture sliding the measured portion of the base to the right. Do you "see" that the area becomes larger without any of the unlabelled information changing?

This shows that the posted information is not sufficient, of itself, to enable you to determine the area of the left-hand triangle or of the entire triangle. It is sufficient only to find the area of the right-hand triangle. :wink:
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Re: Finding the Area of a Triangle

Postby cruxxfay on Thu Aug 16, 2012 3:04 am

Thank you for the answer. I was doing a Pre-IB course and thought there would be an advanced way of solving this. But anyway thanks :D
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