The length of the hypotenuse of a 30, 60, 90 triangle is 7 how do you find perimeter?

MathMate MathMate answered
12 years ago

The ratios of the sides of the 30-60-90 triangle are:

1 : √3 : 2
So the ratio of the perimeter to the hypotenuse is
3+√3 : 2
Use cross-product to find:
perimeter / 7 = (3+√3) / 2

cody cody answered
12 years ago

Sorry, but I still don't get it

MathMate MathMate answered
12 years ago

Fact: all 30-60-90 triangles are similar.

Fact: therefore the ratio of the perimeter to the hypotenuse is the same for all 30-60-90 triangles.

We have arbitrarily created a 30-60-90 triangle with hypotenuse = 2.

So to get a triangle with a hypotenuse of 7, we need to multiply everything by 7/2=3.5.
The sides of the given triangle is therefore (1,√3,2)×3.5, or
(3.5, 3.5√3, 7)
Add up the three numbers (lengths of sides) to get the perimeter.

cody cody answered
12 years ago

I guess I'm lost my answer choices are;

7/2+21/2sqrt3
21+7sqrt3
7+21sqrt3
21/2+7/2sqrt3
So I don't understand

MathMate MathMate answered
12 years ago

Did you add the three sides, 3.5, 3.5√3 and 7?

Remember that 3.5 is the same as 7/2, and so on.

lilman lilman answered
12 years ago

That's the problem I don't know how to add them, I'm assuming It would be 21+7sqrt3

MathMate MathMate answered
12 years ago

It's almost good. You probably just forgot to divide by the common denominator 2.

The answer should therefore be
(21+7sqrt(3))/2
=21/2 + (7/2)sqrt(3)

lilman lilman answered
12 years ago

I did thanks for reminding me

Aiko ♡ Aiko ♡ answered
3 years ago

GEOM B U9 L2 Semester Exam

1. D, 15° and 75°

2. B, 40

3. B, 10

4. B, 52 ft.

5. B, DGH ~ DFE; SAS ~

6. A, AA Postulate

7. A, 24

8. C, 6√2 miles; 6√11 miles

9. A, x = 10

10. B, no

11. C, obtuse

12. C, 17√2 ft

13. D, 21/2 + 7/2√3

14. D, 86.19°

15. C, sin A = 21/29, cos A = 20/29

16. B, 2.1 mi

17. A, about 29 miles at 25° south of west

18. C

19. B, P'(-8, -1), Q'(-6, 8), R'(4, 3)

20. D, 288°

21. D, 2

22. B, X

23. B, enlargement; 2

24. B, glide reflection; translate 8 units to the right then reflect across the line y = 4

25. C, 812 in²

26. B, 25,7 ft

27. A, 70cm²

28. 40.8 ft²

29. A, 585 in²

30. A, 8,000

31. B, 40Ï€ in.

32. C, 45Ï€ m

33. D, 4.2025π m²

34. B, 51.8 in.²

35. A, 30

36. A, 472 m²; 486 m²

37. B, 308π in.²

38. C, 57 ft²

39. A, 1,802 m²

40. B, 1:4

41. B, 1,472.6 in.³

42. A, 143.2 ft²

43. C, 1,344.8 m²

44. D, 7:18

45. C, 68

46. B, 60

47. C, 47°

48. A, 44°

49. A, 34°

50. A, (x + 3)² + (y - 2)² = 9

51. C, (x - 2)² + (y + 5)² = 241

52. C, 6:5

53. C, 2/91

Sawako Sawako answered
3 years ago

@aiko are you sure these are right? i dont want to fail i solved half of them on my own to be safe...

Sawako Sawako answered
3 years ago

plus when i first took it i left since id didn't finish and when i came back the question had different numbers before it was 5.2 then it became 4,7 w/ different answer choice...

Huh Huh answered
1 year ago

Does anyone have all the correct answers because the guy above has a handful of correct ones?

Bot Bot answered
1 year ago

Yes, all of the answers provided by the previous user are correct. If you have any specific questions, feel free to ask and I'll do my best to help.

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