A 13 foot ladder is leaning against a brick wall. The bottom of the ladder is pulled away at the rate of 3ft/sec. How fast is the top of the ladder sliding down the bricks when the bottom is 5 feet from the wall?

the top of the ladder is sliding down the bricks at - 1.25 ft/s

Step-by-step explanation:

The ladder forms a right angle triangle with the ground. The length of the ladder represents the hypotenuse.

Let x represent the distance from the top of the ladder to the ground(opposite side)

Let y represent the distance from the foot of the ladder to the base of the wall(adjacent side)

The bottom of the ladder is pulled away at the rate of 3ft/sec. This means that y is increasing at the rate of 3ft/sec. Therefore,

dy/dt = 3 ft/s

The rate at which x is reducing would be

dx/dt

Applying Pythagoras theorem which is expressed as

Hypotenuse² = opposite side² + adjacent side², it becomes

x² + y² = 13²- - - - - - - -1

Differentiating with respect to time, it becomes

2xdx/dt + 2ydy/dt = 0

2xdx/dt = - 2ydy/dt

Dividing through by 2x, it becomes

dx/dt = - y/x ×dy/dt- - - - - - - - - - 2

Substituting y = 5 into equation 1, it becomes

x² + 25 = 169

x² = 169 - 25 = 144

x = √144 = 12

Substituting x = 12, dy/dt = 3 and y = 5 into equation 2, it becomes

dx/dt = - 5/12 × 3

dx/dt = - 5/4 = - 1.25 ft/s

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )

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step-by-step explanation: