Pleas help exam tommarow Trigonometry word problems

[Aya]

Pleas help! exam tommarow! Trigonometry word problems

Hi, i really need help with this question,

on 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 oll have one measure ment 100cm? Can someone pleas help me through the problem? I really don't know where to start

 

[HallsofIvy]

The fly is moving horizontally at 10 cm/s. In "t" seconds, it will have moved 10t cm from directly below the spider. If the spider at 20 cm/s, 1 second after the fly, t seconds after the fly started moving), it will have moved 20(t- 1) cm. (do you see why it is "t-1"?) If you draw the three lines connecting the spider's original position, the fly's original postion, and the point where they meet, you will have a right triangle with legs of length 100 cm and 10t cm, and hypotenuse of length 20(t-1) cm. Use the Pythagorean theorem to determine t and then use trig functions to determine the angles in the triangle.