I’m trying to figure out how to draft this acute triangle from a pattern. I have the 4cm to 3.7cm line on the left but am stumped on how to create the point at the 4cm to 3.7cm line on the right. I can use a triangle solver to get the dimensions and plug them in but was hoping to do it the correct, parametric way. What tool am I looking for? Apologies if this is a dumb question, it’s late here (lol).
Looking at the lines, if you’ve drafted the rest of the diagram correctly, then the distance of the right side will be 4cm, so you can just use the Line Between 2 Points tool to draw the line.
If you already have the 1st line at whatever degrees, then you can use the Arc tool to draft 2 arcs that cross over and then use the Interect 2 Arcs tool to place a point at where they intersect.
Since the 2 sides are both 4 - the 2 angles in the red circles are equal.
You can use the math functions and the following formula below to calcuate those angles:
The 3rd angle is 180 - 2 * Angle. I’d have to see what already exists in the pattern to know what tool to use to find the point in red below:
But I can guess that using the Point - Length and Angle tool using 3.7 for the length fx and the calculated angle adjusted to the angle of the line that the basepoint is on for the angle fx:
Point - Intersect Circles tool in the Arc toolbox to place a point at the intersection of 3.7 from the left point, & 4 from the point that the two 4 unit measures come off of. If you really need a visual line there, the Line tool is handy for adding that afterward.
It is much easier than using trigonometric functions. 
Thanks everyone for the tips. I finally went with Grace’s solution, but I tried to walk through/understand Douglas’ formula-based way of doing it. I’m sure I’ll eventually need to know some formula wizardry at some point. I posted a zoomed-in pic just to illustrate that one acute angle. Here is the image with more context:
That “kinda” squared off 3.7cm line is just for clarity, it isn’t really used as the pattern develops (you can see, it isn’t even mirrored over to the other side for the lapel/collar construction).
Thanks everyone again!
Aaaahhh… Thanks for this pic. I couldn’t figure out what you were doing… Perhaps some very small quilting? If you’d shown @Douglas that image from the start, I’m sure he would’ve skipped the trig lesson 