Which number is greater 87 or 13.688 how do you know

The square root of 9x plus 7 plus the square rot of 2x equall to 7

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

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !