Answer:
<em><u>1 and 5</u></em>
Step-by-step explanation:
The squares have a side length of 10 and 1 square side is the radius of the half-circles. Since there are two half-circles, find the circumference for one full circle:

Insert the radius:

Simplify pi:

Simplify multiplication:

The circumference of the circles is 62.8. Now find the perimeter of the exposed squares with side length 10. There are 4 exposed sides, which equals one square. Find the perimeter:

Add the perimeter of the circle and the square together:

Now see which of the options gives you the perimeter:
1.
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2. 
3. 
4. 
5.
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Finito.
I used similarities in triangles
For this case we have by definition, that the volume of a cone is given by:

Where:
A: It is the cone radius
h: It's the height
They tell us that the diameter is 21 m, then the radius is half the diameter, that is: 10.5m. The height is 4m. Substituting the data:
.
Finally, the volume of the cube is
ANswer:
Option B