The surface area of a cylinder is define by the formula S.A.=2πrh+2<span>πr^2, where the first part of the formula refers to the lateral area, perimeter, or circumference and the second part to the area of the bases, which are circles.
On this exercise it is asked to find the lateral area of a cylinder whose radius is 6 cm, and has a height of 20cm. To find the lateral area of the cylinder you should substitute this values into the formula, S.A.=2</span>πrh, and as can be seen the answers are given in terms of <span>π or pi.
S.A.=2</span><span>πrh
S.A.=2</span><span>π(6cm)(20cm)
S.A.=2</span><span>π(120cm)
S.A.=240</span>π cm^2
The lateral area of the cylinder is 240<span>π cm^2 or in other words letter B from the given choices.</span>
Solve the following system using elimination:
{7 x + 2 y = -19 | (equation 1)
{2 y - x = 21 | (equation 2)
Add 1/7 × (equation 1) to equation 2:
{7 x + 2 y = -19 | (equation 1)
{0 x+(16 y)/7 = 128/7 | (equation 2)
Multiply equation 2 by 7/16:
{7 x + 2 y = -19 | (equation 1)
{0 x+y = 8 | (equation 2)
Subtract 2 × (equation 2) from equation 1:
{7 x+0 y = -35 | (equation 1)
{0 x+y = 8 | (equation 2)
Divide equation 1 by 7:
{x+0 y = -5 | (equation 1)
{0 x+y = 8 | (equation 2)
Collect results:
Answer: {x = -5, y = 8
Starting from the fundamental trigonometric equation, we have

Since
, we know that the angle lies in the third quadrant, where both sine and cosine are negative. So, in this specific case, we have

Plugging the numbers, we have

Now, just recall that

to deduce

Answer: 9
Step-by-step explanation:
From doing the math I think it should be 9