11. Sketch the circles x2 + y2 = 9 and x2 + y2 - 18x + 72 = 0. Find the equation of the
circle whose centre is on the x-axis and which
touches both of these circles:
(i) Externally
(ii) Internally

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