Please help with:

[Guest]

Hi, i really need help with this question,

An a wall, a spider is 100cm above a fly. The fly starts moving horizontally at the speed of 10cm/s. After 1s, the spider begins moving at twice the speed of the fly, in such a way as to intercept the fly by taking a straight line path. In what direction does the spider move, and how far has the fly moved when they meet?

How do I do this question? It just sayes the fly moved horizonally. How do you know witch way it went? Won't that determine where the spider went? And I only have one measurement: 100cm. Can someone please help me through the problem? I really don't know where to start :shock:

 

[galactus]

Use Pythagoras.

Here's a picture aka.

distance = rate*time

From the triangle, the distnace the fly will have travelled is 10t cm.

The spider leaves 1 second later and runs twice as fast as the fly, so his

distance travelled is 20(t-1).

We know he was initailly 100 cm from the fly.


So, we have the equation:

\(\displaystyle \L\\\sqrt{(10t)^{2}+(100^{2})}=20(t-1)\)

Solve for t.

 

[Guest]

^ ok, thanks! but I have more problems!

An equalateral trianhgle ABC has been creased and folded so that its vertex A now rests on BC at D, such that DB= 1 and DC =2. find the length of
a) AP
b) AQ
c) PQ

so eualatera triangle that means all the angles are the same measurment right? so all are 60 degrees, but what elce can I do???


Thanks for your help

 

[Denis]

Did you "cut" yourself an equilateral triangle, and fold it?

AND: WHERE are points P and Q ?

If you want help, please post clearly and in full.