Answer:

Step-by-step explanation:
Given
AB = 48, AC = 64, and BC = 80
Required
Determine the ratio of cosB
The first step is to determine, which type of triangle it is.
Checking for Right Angled Triangle
For a triangle to be a right angled triangle, the square of the largest side must be equal to the sum of squares of other sides
This implies that:



<em>Hence, the triangle is a right angled triangle [See attachment]</em>
From trigonometry;

The adjacent of B = 48 while the hypotenuse is 80;
Hence;

Hence, the ratio of cos B is 