# Shawl Geometry: Right Triangle

*This is the fourth post in a series about different shawl shapes and how to knit them. All the posts in the series can be found right here.*

# Right Triangle from the top down

If you take a square and cut it in half diagonally, you’ll be left with two right triangles. So, working half of the shaping for a Square Knit in the Round, will give you a Right Triangle shawl.

The Right Triangle is shaped using a pair of increases (or decreases) down the center spine, and a single increase (or decreases) along either edge, all worked every other row.

### Knitting Instructions

CO 7sts.

{4 border sts + 2 sections + 1 spine}

R1: k2, yo, k1, yo, pm, k1, pm, yo, k1, yo, k2.

R2: purl across.

R3: k2, yo, k to marker, yo, sm, k1, sm, yo, k to last 2sts, yo, k2.

R4: purl across.

Rep R3&4 to desired dimensions.

Bind off loosely.

# Right Triangle from the bottom up

Just like the Square Knit in the Round, can be worked from the center out and the hem in, this Right Triangle can be worked from the top down or the bottom up. This makes sense since a triangle is half a square.

### Calculating your cast on

Determine your final gauge, and desired depth down the center spine.

[Desired depth] / 2 = [Z]

[Z] x [1.4142] = [magic number]

[Magic number] x [row gauge] = [# of rows]

[# of rows] / 2 = [# of dec rows]

[# of dec rows] x [4sts decreased per dec row] = [# of sts decreased]

*Make sure this number is divisible by 4.*

[# of sts decreased] = [# of sts to CO]

### Calculating your stitch marker placement

[# of sts to CO] / [2 shawl sections] = [# of sts in one section aka Y]

### Knitting Instructions

CO [# of sts to CO].

R1: ssk, kY minus four, k2tog, pm, ssk, kY minus four, k2tog.

R2: purl across.

R3: ssk, k to 2sts before marker, k2tog, sm, ssk, k to last 2sts, k2tog. R4: purl across.

Rep R3&4 to 4sts.

Bind off loosely.

Both of these methods create shawls that are half squares and right triangles. Some people find these a little bit hard to wear in that they slide off the shoulders and are therefore a little bit fiddly. So over the next two weeks we’ll talk about two variations that I think are a little easier to wear, a Shallower Triangle and a Right Triangle with “Wings.”

These are simply the basics, backwards and forwards. These basics can then be manipulated and expanded upon and played with to create a myriad of other shawl shapes. However, these shapes are incredibly powerful on their own, add patterns & textures, lace, cables, knits/purls, color work, anything you can think of.

#### The previous post: Octagon Circle

The next post: Shallower Triangle