Posted by christina on Sunday, October 20, 2013 at 10:53pm.
Two sides of a triangle have lengths 15 m and 18 m. The angle between them is decreasing at a rate of 0.08 rad/s. Find the rate at which the area of the triangle is changing when the angle between the sides of fixed length is 120°.

math  Reiny, Sunday, October 20, 2013 at 11:13pm
Using the formula:
area = (1/2) ab sinØ , where a and b are the sides and Ø is the contained angle
A = (1/2)(15(18)sinØ
A = 135 sinØ
dA/dt = 135 cosØ dØ/dt
given: dØ/dt = .08 , and cos 120° = .5
dA /dt = 135(.5)(.08) = 5.4 m^2
when the angle is 120°, the area is increasing at 5.4 m^2/s

math  fak u, Wednesday, September 2, 2015 at 5:52am
0.9
Answer This Question
Related Questions
 math  Two sides of a triangle have lengths 8 m and 24 m. The angle between them...
 Math  The two sides of a isosceles triangle have a fixed lenght of 14 cm. The ...
 Math  The two sides of a isosceles triangle have a fixed lenght of 14 cm. The ...
 Math  The two sides of a isosceles triangle have a fixed lenght of 14 cm. The ...
 Math  The two sides of a isosceles triangle have a fixed lenght of 14 cm. The ...
 Calculus  1) Find correct to six decimal places root of the equation cos(x)= x ...
 Trigonometry  Two sides of a triangle are 5 and 8 units respectively. If the ...
 trigonometry  In the triangle ABC, the sides AB and BC have lengths 7cm and 8cm...
 Calculus  Two sides of a triangle have lengths 8 m and 13 m. The angle between ...
 math  two equal sides of an isoscles triangle with fixed based 'a' are ...
More Related Questions