Jin purchased 7 tacos for 18.55 how much will he pay for 15 tacos

How do you find the circumfrance of a circle?

2x minus y equals 6, x plus y equals negative 3

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