PLS HELP

Mathematics

1 answer:

djyliett [7]2 years ago

4 0

Answer:

Look at the unfolded cylinder down: it's consisted of a rectangle and 2 circles. so to find the surface area of the cylinder we should find the areas of the rectangle and the 2 circles.

1) A of 2 circles = 2(π $r^{2}$ ) = 2π $r^{2}$

2) A of rectangle = base x height (or length x width) = bh

but the if we fold the rectangle? what will happen?

the base will go around the circle, this means that the base is equal to the circle circumference, which is 2πr.

Therefore, A of rectangle = 2πrh

3) Surface area of cylinder = 2π $r^{2}$ + 2πrh

simplify more and take the common factor 2πr:

= 2πr (r+h)

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A portion of a roller coaster track is shown in the figure above. the roller coaster track is shown at ground level at point S a

eimsori [14]

Answer:

Step-by-step explanation:

This is classic right triangle trig. The height of the hill is 78.4 which serves as the side opposite the reference angle of 23 degrees. The side we are looking for is the hypotenuse of that triangle. The trig ratio that relates the side opposite a reference angle to the hypotenuse of the right triangle is the sin ratio. Setting it up using our values:

$sin(23)=\frac{78.4}{x}$ , where x is the unknown length of the hypotenuse. Solving for x: