I'll solve 21, and you then should be able to solve the rest on your own!
Since ADC is 135, that means that that whole angle is 135 degrees. In addition, since angles ADB and BDC add up to ADC, we get ADB+BDC=ADC=135=11x+9+7x=18x+9. Subtracting 9 from both sides, we get 126=18x. Dividing both sides by 18, we get x=7. Plugging that into 11x+9=BDC, we get 11*7+9=77+9=86
Answer:
240
Step-by-step explanation:
add up the numbers of all the students that were surveyed
get 90
60 of those were rock or hiphop
divide 360 by 90
get 4
multiply 60 by 4
get 240
Right ankle is exactly 90 degrees, while obtuse is more than, and acute is less than