In triangle abc, ac = 15, bc = 11, and m∠c = 75. to the nearest tenth, what is the length of ab¯¯¯¯¯¯ ?

AB = 16.14279 units

Explanation:
To solve this question, we will use the cosine rules shown in the attached image.
We are given that:
a = BC = 11
b = AC = 15
c = AB that we want to calculate
measure angle C = 75 degrees

We will substitute in the third rule to get the value of c as follows:
c^2 = a^2 + b^2 - 2ab*cos(C)
c^2 = (11)^2 + (15)^2 - 2(11)(15)cos(75)
c^2 = 260.589
c = 16.14279 units
Therefore:
AB = 16.14279 units

Hope this helps :)

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm