Given that ∠ADC≅∠BCD, AC⊥CD and BD⊥CD, which of the following proves that △ACD≅△BDC?

Satchi found a used bookstore that sells pre-owned dvds and cds. dvds cost $9 each, and cds cost $7 each. satchi can spend no more than $45.

Which table shows a proportional relationship between miles traveled and gas used?

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81