1. dismal 2. wager 3. peril 4. recline 5. shriek 6. sinister 7. conceal 8. inhabit 9. frigid 10. numb 11. corpse 12. tempt
1. BC is 1+3=4 (units)
2. AD is 3+5= 8 (units)
3. Draw the altitude CH from point C, as shown in the figure.
4. Then triangle CHD is a right triangle, with hypothenuse CD, and sides HD and CH.
5.



6. AB=CD=4.47 because the trapezoid is isosceles.
7. P= BC+AD+AB+CD=4+8+4.47+4.47=20.9 (units)