if a certain number x is doubled, the result is less than or equal to 12. find the range of values of the number

Two lines parallel to the same plane are parallel to eachother

What is the volume of a cone with a height of 6 cm in the radius of 2 cm

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap