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 
X jumpers at <span>£15 each. Total = 15*x = </span><span>£15x
</span>
y shirts at £12 each. Total = 12*y = <span>£12y
Total cost = </span><span>£15x + </span><span>£12y
Total cost = </span><span><span>£(15x + 12y)</span></span>
2x+38=180
2x=142 (or x+x=142 from which 2x=142)
x=71
The unknown angles are each 71
You know this answer is logical as, since two sides are 21 it hints that we are looking at an equilateral triangle, which means two of its angles will be the same
Answer:
8.4
Step-by-step explanation:
0.9c - 2.3d
given c = 17 and d = 3, substitute these into the expression:
0.9c - 2.3d
= 0.9(17) - 2.3(3)
= 15.3 - 6.9
= 8.4