Math question

[applestar]

… it’s been too long …

Could someone tell me the length of the yellow arc? I need to figure out what size greenhouse film I need for my Sunflower House…. Thank you!

[HoneyBerry]

there are 2 ways to interpret this

this assumes that the yellow is a half circle with 2 short straight segments

the radius is 38.5 in this calculation ( 77 divided by 2 )

c = 2 x pi x r
c = 2 x 3.14 x 38.5
c = 241.78

241.78 divided by 2 = 120.89

120.89 + 7.5 + 7.5 = 135.89

please get a 2nd opinion
it’s been a while for me too

[HoneyBerry]

I checked this graphically and 135.9 is the correct length, if an arc with 2 short straight segments. The straight segments would each be 7.5

Another way would be for the arc have a 46 inch radius and no straight segments. It would be slightly bowed at the bottom where it meets the top of the wall.
I did this graphically and the length of the curve measures 136.7

[applestar]

I love it! That’s a great way to break the problem down. Thank you thank you!

[pepperhead212]

The problem here is that's not a perfect arc - if this were the case, the height would be half of 77, or the diameter would be double 46, or 92. Then, in each case the arc would be half the circumference, which is 2πr. So the 180° arc, if in a circle, would be πr. So if 46 was the radius, it would be about 144.5. And if the radius was half of 77, or 38.5, the arc would be about 120.95. So you are going to need somewhere in between these, and I would err on the larger side

[applestar]

Yep yep. I’m getting a good approximation and then will go slightly bigger just in case.

Thanks

[Gary350]

92 x pi ÷ 2 = 144.5

Easy way to solve this problem is circumference divided by 2

92 x 3.14159 = 289

289 ÷ 2 = 144.5

If you want to double check cut a piece of paper 144.5 then bend the radius see how it turns out.