The surface area of a cylinder with circular bases of radius <em>r</em> and height <em>h</em> is equal to the sum of the areas of the two circular faces and the area of the rectangular lateral surface:
<em>A</em> = 2π<em>r</em>² + 2π<em>rh</em>
If you know the height <em>h</em>, then you can solve the quadratic equation for <em>r</em>.
Answer:
117.8
Step-by-step explanation:
Surface area = πr²+πrl (whee r = radius and l = slant height)
= π×3²+π×3×9.5
= 75π/2
= 117.8
There are 15 marbles in the bag. This gives us the probability of picking a red marble as 5/15, or 1/3. Because you replace the marble therefore making the probability the same each time, and as it's a logical 'and' operation, you multiply the probabilities like this:
(1/3)•(1/3)=(1/3)^2
Because (a/b)^c = a^c/b^c, P(two red marbles) = 1^2/3^2 = 1/9.
