Which country is this? I think both American and European (or at least Norwegian) washers use standard plugs (although American dryers do not), so I'm just curious which areas use something custom for that.
A regular plug should be able to supply a washer with power, but dryers are a different story in countries using 110V power.
There's less and less reason to do it (and it's never 5). On systems without floating point you might want to round it a bit, but only if the specific thing you're doing allows it, and even then you're more likely to do a fixed-point approach by using e.g. 314 and dividing by 100 later, or adjusting that value a bit so you can divide by 128 via bitshift if you're on a chip where division is expensive. However, in 2025 you almost certainly should have picked a chip with an FPU if you're doing trigonometry.
And while rounding pi to 3 or 4 is certainly just a meme, there are other approximations which are used, like small-angle approximations, where things like
sin(x)
can be simplified to justx
for a sufficiently smallx
.