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/sci/ - Science & Math

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File: 6 KB, 528x215, beltlength.png [View same] [iqdb] [saucenao] [google]
4668875 No.4668875 [Reply] [Original]

How do I calculate the length of the belt in the image?

>> No.4668880

>inb4 homework

>> No.4668881

add up all the lengths

>> No.4668885

half the circumference of the small + half the circumference of the big + 2 times the square root of ((r2-r1)^2+d^2)

>> No.4668886

pi*(r1 + r2) + 2sqrt(d^2 + (r2 - r1)^2)

>> No.4668889

>>4668875
with trigonometry.

>> No.4668890

pi*r1/2 + pi*r2/2 + ( 100^2 + 900^2) ^(1/2)
sorry i dont know latex

>> No.4668892

This isn't homework, I need a replacement belt for my crazy ideas machine.

>> No.4668895

>>4668875

sides (r2-r1) and d create a right triangle, use Pythagorean theorem.

>> No.4668897

>>4668890
>implying semicircles

>herp. tangent to a circle is not going to make each a semicircle

>> No.4668899

>>4668890
damnit forgot 2 for pyth.

>> No.4668902
File: 56 KB, 630x395, sohcahtoa-mnemonic-device.gif [View same] [iqdb] [saucenao] [google]
4668902

guys

the belt does not touch the circles directly above and below the centre

>> No.4668912

>>4668897
>implying OP is actually designing the belt and not doing an over simplified trig homework problem.

>> No.4668913

>>4668902
sure it does

>> No.4668930

<span class="math">200(\sqrt{85}+500\pi)[/spoiler]