37 replies to this topic

[terry1966]

ok remembered pyphagoras therom(thanks google) for working out a diagonal, and according to my numbers 43.17(close to oldmans original answer) walking the diagonal isn't shorter than straight down,across and up. 10 x 42 corner to corner is what i made it the spider needs to walk. so i'm now officially out of answers.

Edited by terry1966, 11 September 2012 - 10:34 PM.

[Tomk]

I'm guessing that you have made the same "mistake" that om960 did... but the Pythagorean theory (a² + b² = c²) can be quite useful in solving this. You might also want to keep in mind one of Euclids postulates: "The shortest distance between two points is a straight line".

[terry1966]

by my calculations the straight line is 42foot if she walks along the floor or ceiling and 43.17foot if she walks a diagonal line along the walls. i just don't see how else you would get a straight line between those 2 points if no web is used. the shortest distance if she could walk on air would be 31.62 feet like oldman posted earlier.

Edited by terry1966, 13 September 2012 - 01:39 AM.

[terry1966]

i think the answer your looking for is 41.66 feet. but by my calculations it's wrong. if she walked diagonally down the end walls but straight across the side wall. she would walk 7.81(6x5) feet along the first end wall to get to the half way point between top and bottom of the 10 foot distance then 30 foot across and another 7.81 (6x5) feet diagonally again on the other end wall to get to where she wants to be, which is a total of 45.62 feet. i think you just used 6x10 to get the 11.66 foot and then added it to 30 foot length to get the 41.66 foot answer. (if that is the answer your after.) instead of 12x10 because there are 2 end walls or you failed to take into consideration she would then have to walk another 6 foot to get from the side wall to the centre of the other end wall.

Edited by terry1966, 13 September 2012 - 02:50 AM.

[Tomk]

I don't recall using any "6x10". The path you have described does not seem like a straight line between point A and point B.

[terry1966]

well i'm out of answers tomk, that was the only way i could come up with an answer smaller than 42foot, using an error in my logic/caculations. unless the "other end wall" is in the next room and is just the other side of the one she's on, then she'd walk about 12 foot, along the wall through the door and along the other wall to get to the point she wants. must admit i'd love to know your answer so i can try and figure out how you came up with it.

Edited by terry1966, 13 September 2012 - 11:28 AM.

[Tomk]

HINT: Take a cardboard box. Scale doesn't matter. Mark to spots inside it to represent (roughly) the two points in our problem. No, with a straightedge... draw a line between the two points.

[oldman960]

How's this? Far is a term used to express the space between locations. In this case she would only be 30' from where she started out.

[Tomk]

yep. But how far did she walk to get there? I strongly suspect that if you draw the line in a cardboard box the way I suggested... you'll get the answer.

[terry1966]

i still get 42 foot. shrugs. 11 foot down first wall 30 foot across floor and 1 foot up other end, or 1 foot up, 30 foot across ceiling and 11 foot down.

[Tomk]

Try the cardboard box trick.. HINT #2: You will have to unfold the box to use a straightedge to make a line.

[terry1966]

there's noway i know of to make 11, or 1 foot shorter when it's upright or laying down, didn't have an empty box so just folded the ends on a piece of paper to make the walls. my measurements when laid flat made the distance slightly longer than i expected(probably due to the folds), not shorter so to be honest tomk, i'm beginning to think you've made a mistake somewhere. either that or i'm being totally stupid, and i wouldn't bet against that possibility.

[Tomk]

Last HINT: To take the most direct route (=shortest route) our spider will have to walk on both end walls, one side wall, and both the floor and the ceiling.

[terry1966]

ah, a spiral or parallelogram joined at one end... (not exactly what i'd call a straight line, when laid flat. ) mmmm guess that means walking at a 45 degree angle or something, no idea how to work that out, memories not good enough, looks like a bit of googling is needed for me to solve it, so i will give it a few days to see if someone else can work it out before i start googling.

[Tomk]

Nope... no spiral. A straight line that you can draw on your box with a straightedge.