On a calculator display, some years look the same upside down as right side up. What is the first such year in the 21st century?

The first such year is 2002.

Step-by-step explanation:

For them to be the same upside down as right side up, the first and last digit have to be the same.

Since we are in the 21st century, and the years begin with 2, then have to end with 2. So

2xx2.

Numbers that look the same upside down as right side up are: 0,1,2,5,8. So, the first possible year is:

2002

  21.3

step-by-step explanation:

multiplying the given equation by c/sin(25°), we get

  c = 9/sin(25°) ≈ 21.2958 ≈ 21.3

we assume "c" is the length of ab, the side opposite angle c in triangle abc.

1. 3.4/4

2. 0.8/7

3. 0.5 x 3

4. 0.9 x 6

5. 10.8

6. 2.35

7. 0.567

8. 9.35

9. 0.02

10. 0.06

11. 0.16

12. 0.42

13. 0.63

14. 5.6

15. 8.1

16. 9.9

17. 0.28

18. 0.48

19. 0.27

20. 0.49

21. 0.45

22. 0.72

23. 0.9

24. 0.88

25. 0.75

26. 0.16

27. 0.328

28. 0.495

29. 0.72

30. 1.068