When I was in high school I was a square who liked to play with triangles. I took advanced algebra and geometry because I enjoyed them. I never figured any of that stuff would actually apply to my real life. And then I came to quilting! But I avoided triangles as much as possible because I never could quite figure out how to make the points sharp. And figuring out how to draft a block with triangles in it made me bleary eyed. But then I saw the relation my math background had with the creation of simple triangles. There really are tried and true formulas to figure out those pesky triangle measurements with a very accurate yield. This lesson will cover two of the most common triangles quilters use and then show you some tips and tricks in how to use these triangles to conquer some fairly pesky blocks. (Anything with a set in seam qualifies as a pesky block with me.)

The two most common triangles are the right triangle and the equilateral triangle. The right triangle has two of its three sides perpendicular to each other, thereby forming a 90 degree angle. The bottom (base) is perpendicular to its height (leg). The equilateral triangle is one in which all the sides are equal in length.

A half-square triangle is half of a square. Cut a square 7/8"
larger than the **finished** size of the square unit. For example,
for a 4" finished square, cut 2 squares of fabric 4-7/8"

Draw a diagonal line on the wrong side of the lighter fabric. Place squares right sides together and sew 1/4" on both sides of the drawn line. Cut along this line. Press toward the darker fabric. Yields 2 half-square triangle squares which are 4" finished.

A quarter-square triangle is one fourth of a square. Cut a
square of fabric 1-1/4" larger than the **finished** size
of the square unit. For example, for a 4" finished square,
cut 2 squares of fabric 5-1/4". This will yield two quarter-square
triangle units.

Draw diagonal lines on the wrong side of the lighter fabric. Either cut along these lines and sew contrasting triangles together along one short side or place squares right sides together and sew 1/4" on both sides of both lines. Cut along the drawn lines. Press toward the darker fabric. Yields two quarter-square triangle blocks/units.

This block is composed of three triangles. The larger triangle is a half square triangle. The two smaller triangles are two units from a quarter-square triangle block. Use the formulas described above to determine cutting sizes.

Why struggle with set-in seams when you can convert this to
an easy piecing dream? Draw imaginary lines so that you see the
half-square triangles. Use the half-square triangle formula to
construct your **LeMoyne Star** as indicated above.

An **Ohio Star **is based on a 16 grid. If the finished
block is 12" then each unit is 3" square. The star points
can be made using the half-square triangle method.

The **Spool Block** is simply constructed using rectangles,
half square triangles, and a larger central square. What could
be easier?

This method of using half-square and quarter-square triangles
is a simpler way to approach other blocks, too. Consider using
this technique to piece the** Attic
Window **block and also to make **Flying
Geese**. There are endless possibilities to your creativity
when you no longer fear the math involved in those pesky triangles.

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