trigo--help!

posted by .

how do i do this question?

a ladder length 13m rests against a vertical wall with its foot on a horizontal floor at a distance of 5m from the wall. when the top of the ladder slips down a distance of x, the foot of the ladder moves out x. find the distance of x.

a^2 + b^2 = c^2
a^2 + 5^2 = 13^2 ==> 169-25=144=a^2
therefore a = 12
after adjustment;
(12-x)^2 +(5+x)^2 = 13^2
144 - 24x +x^2 + 25 + 10x +x^2 = 169
2x^2-14x=0
x(2x-14)=0
x = 7 or 0
Therefore the distance moved is 7m.

thanks!

but shouldn't it be 0 or -7?

oh, sorry, i get it

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Mathematics

    A Ladder AB, of length 13m, rests against a vertical wall with its foot on a horizontal floor at a distance of 5meters from the wall. When the top of the ladder slips down a distance x meters on the wall, the foot of the ladder moves …
  2. algebra

    A ladder is resting against a wall. The top of the ladder touches the wall at a height of 15 feet and the length of the ladder is one foot more than twice the distance from the wall. Find the distance from the wall to the bottom of …
  3. maths

    A ladder lies against a wall.the top of the ladder reaches 8feet above the ground. when the ladder slips 2meters away from the wall,the top of the ladder touches the foot of the wall.then length of the wall?
  4. Calculus

    a 5m ladder rests against a vertical wall. The top of the ladder begins sliding down the wall at 2m/sec, while the foot of the ladder moves away from the base of the wall. How fast is the foot of the ladder moving away from the wall …
  5. math

    A ladder 10 m long rests on horizontal ground and leans against a vertical wall. The foot of the ladder is pulled away from the wall at 2 m/s. How fast is the top sliding down the wall when the foot of the ladder is 6m from the wall?
  6. Physics

    An 8.5 m ladder whose weight is 310 N is placed against a smooth vertical wall. A person whose weight is 515 N stands on the ladder a distance 1.8 m up the ladder. The foot of the ladder rests on the floor 5.78 m from the wall. Calculate …
  7. phsics

    uniform ladder 25 ft long rests against a smooth vertical wall. The ladder weighs 15 Kg. The lower end of the ladder is 15 ft from the wall. A man weighing 80 Kg climbs up the ladder until he is 20 ft from the base of the ladder, (20 …
  8. maths

    A 25m ladder is leaning against a vertical wall. The floor is s lightly slippery and the foot of the ladder slips away from the wall at a rate of 0.3m/ s. How fast is the top of the l adder sliding down the wall when the top is 20m …
  9. Physics

    A ladder ABC of length 20m is leaning against a wall at an angle from the horizontal. There is a roller at the top of the ladder that rests against the vertical wall. The coefficient of friction between the ladder and the horizontal …
  10. Calculus (related rates)

    A ladder 13 meters long rests on horizontal ground and leans against a vertical wall. The foot of the ladder is pulled away from the wall at the rate of 0.4 m/sec. How fast is the top sliding down the wall when the foot of the ladder …

More Similar Questions