Isosceles Triangle

The yellow triangle has two equal sides.
The yellow triangle has two equal sides.

An isosceles triangle is sometimes used in piecework. More advanced piecing skills are needed when dealing with this type of triangle as at least two of the sides will always fall on the bias. This triangle is different from the half square triangle as it does not have any right angles.

Watch the video below to find out how to cut an isosceles triangle using your rotary cutter.

You will also get hints and tricks for sewing triangles accurately and links to other free videos about cutting formulas. 

The 7 featured triangles along with the time they appear in the video are: 

  1. Half Square Triangles (HST’s) (1:36)
  2. Quarter Square Triangles (QST’s) (2:25)
  3. Equilateral Triangles (3:34)
  4. Isosceles Triangles (6:06)
  5. Scalene Triangles (7:05)
  6. Corner Setting Triangles (8:28/9:30)
  7. Side Setting Triangle (8:28/9:37)


  1. Wow! What a complete, concise, specific easy to follow set of directions for all the different triangles! This has been absolutely fantastic. Thank you so much

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