Answer:

Step-by-step explanation:
Let the third side of the triangle be
.
We can apply the cosine rule to find
.

We evaluate to obtain;



We take the positive square root of both sides to obtain;

The correct answer is B.
Let the 2 integers be
x and
y.
Their product is 72, so we write:
xy=72. (I)
One of them, say
y, is 2 less than 5 times the other. We can write this as the equation:
y=5x-2. (II)
To find one of numbers, say x, we can substitute y with 5x-2, in the first equation:
xy=72,

expanding the left hand side expression we get:

.
Answer: C
Complement angles means that the sum of the two angles equal to 90°.
Thus,
x + 8x = 90
9x = 90
x = 10°
8x = 80°
The complement is 80°
Step-by-step explanation:
= (11+13+14+15+18+20+23+26)/8
= 140/8
= 17.5