The triangles above are similar.
Calculate the perimeter of the larger triangle.
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The triangles above are similar.
Calculate the perimeter of the larger triangle.
We calculate the perimeter of the smaller triangle (top):
Due to their similarity, the ratio between the sides of the triangles is equal to the ratio between the perimeters of the triangles.
We will identify the perimeter of the large triangle using :
36
If it is known that both triangles are equilateral, are they therefore similar?
Look for matching colors or similar positions in the diagram. The side labeled 3.5 corresponds to the side labeled 14 because they're both the longest sides of their respective triangles.
If the triangles are truly similar, all ratios must be equal. Getting different ratios means either the triangles aren't similar or you made a calculation error - double-check your work!
Yes! Any pair of corresponding sides will give you the same scale factor. Choose the pair that's easiest to calculate with - often the ones with simpler numbers.
Since all sides are enlarged by the same scale factor, the perimeter is also enlarged by that same factor. This saves time: 9 × 4 = 36 is much faster than finding each side individually!
That just means the 'larger' triangle is actually smaller! The process is identical - multiply the original perimeter by your fractional scale factor to get the new perimeter.
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