The half-life of sodium-22 is 2.6 years. A sample contains 800 mg of this isotope. Which expression represents the mass of sodium remaining after h half-lives?

S = 0.5(800)h

S = 800(0.5)h

S = 8000.5h

S = 800h + 0.5

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