# Calculus

In a right triangle, the hypotenuse is of fixed length of 15 units, one side is increasing in length by 4 units per second while the third side is decreasing in size. At a certain instant the increasing side is of length 9 units. Find the rate of change of the third side at the same instant.
a. -3 units per second
b. -5/2 units per second
c. -3/2 units per second
d. -5/4 units per second
e. -3/4 units per second
which on is it? I got -51/8 units per second but that's not right

1. 👍 0
2. 👎 0
3. 👁 308
1. we have

x^2+y^2 = 15^2
x dx/dt + y dy/dt = 0

Let x be decreasing, and y increasing. Then when y=9, x=12, and we have

12 dx/dt + 9*4 = 0
dx/dt = -3

1. 👍 0
2. 👎 0
posted by Steve

## Similar Questions

1. ### Algebra

Which statement about a right triangle is NOT true? A.) The hypotenuse is the longest side of the triangle. B.) The square of the hypotenuse is equal to the sum of the squares of the other two lengths. C.) The sum of the length of

asked by Elizabeth on February 10, 2020
2. ### n2maths

the length of the hypotenuse of a rigth triangled triangle is 10cm more than the length of the longer of the 2sides. calculate the lengths of the hypotenuse and the other unknow n side if the length of the shortest side is 50 cm

asked by alistar on September 17, 2014
3. ### Geometry

Please check my answers 1. A triangle has side lengths of 34 in, 20 in, and 47 in. Is the triangle acute, obtuse or right? a. Right b. Obtuse* c. Acute 2. Quilt squares are cut on the diagonal to form triangular quilt pieces. The

asked by Annoymous on November 18, 2016
4. ### MATH MS.SUE HELP PLEASE!

Could somebody help me I don't understand any of this. Could someone show me or tell me how to work the problems? 1. Find the length of the hypotenuse of a right triangle with the legs of 9cm and 12cm A.8 B.21 C.15 D.225 2.The

asked by bob on October 18, 2013
5. ### Geometry

In right triangle ABC, the median to the hypotenuse has length 15 units and the altitude to the hypotenuse has length 12 units. What is the legth of the shorter leg of triangle ABC?

asked by Jake on January 6, 2011
1. ### geometry

What is the length of the side opposite to a 30 degree angle if it is 12 units less than the hypotenuse of the triangle?

asked by Katelyn on January 14, 2011
2. ### Algebra

Hi. 1. I have a right triangle here. I know that I am to use the Pythagorean Theorem: a^2 + b^2 = c^2. In this case, side a is (x + 4) and b is x. The hypotenuse is 4 + (x + 4) So here we have the equation: (x + 4)^2 + x^2 = 4 +

asked by Student on March 11, 2014
3. ### geometry

In a right triangle, one side is 9 units in length, and the hypotenuse is 15 units in length. What is the length of the other side?

asked by ginA on November 15, 2011
4. ### Math

1. Find the length of the missing side of the right triangle (A triangle is shown to have a base of 15 cm and a height of 8 cm. The slope of it is unmarked A. 289 cm B. 17 cm *** C. 23 cm D. 4.79 cm 2. Find the length of the

asked by Neru on April 3, 2019
5. ### math

The longest side of a triangle is six more units that the shortest side. The third side is twice the length of the shortest side. If the perimeter of the triangle is 25 units, write and solve an equation to find the length of all

asked by Valdo on March 1, 2015

More Similar Questions