# Equations in PTC Creo 7

Today I learned that Creo Parametric has first class support for equations which can be turned into sketch items, and the incorporated into a model. In this example I created a sine wave.

``y = sin(x*2) * 100``

And told Creo to extend it from x=0 to x=900. Here is a picture of editing the equation.

Once I had that curve defined, I created a sketch on the same plane, and then used the “Project” tool to project the sinewave into the current sketch. After adding sides and a bottom, I had a closed shape.

From there it was a simple matter to extrude, offset, cut, and add some colors.

# A big measuring tape and a right triangle

Just a good picture of Eli (with Ezra and Anna in the background) holding a 300′ measuring tape. We needed to make a right angle, so I explained to them that a triangle with the sides

3, 4, 5 will be a 100% right triangle.  So we measured 15′, 20′, and 25′ around three stakes, and that is how we got our right angle :)

For anyone who has been out of high-school long enough to forget, the equation is:

A*A + B*B = C*C

That is…

3*3 + 4*4 = 5*5
9 + 16 = 25
25=25
True

See more about Pythagoras and his Pythagorean Theorem at Wikipedia…