find perimeter of triangle, square; find value of sine; etc

[Guest]

22. An equilateral triangle has an altitude of length 5 square root 3. Find the perimeter.

23. Find the perimeter of the square. (The square has 13 square root 2)

26. sin 74 degrees

27. tan 70 degrees

28. cos 49 degrees

29. x to the nearest degrees, where sin x ~~ 0.7202

30. y to the nearest degrees, where cos y ~~ 0.3880

37. In triangle ABC, m<C = 90 and cos A =1/3. What is the value of tan B? a. square root 2 b. square root 8 c. square root 2 over 4 d. 3


I have a TI-89 Titanium Calculator, and I didn't understand 22, 23, 29, 30, 37. 26-28 is where I want to know do I use cos, tan, sin or cos-1, sin-1, and tan-1. That is all I please need help.[/img]

 

[jonboy]

You should draw these and label the properties.

22. An equilateral triangle has an altitude of length 5 square root 3. Find the perimeter.

An equilateral triangle has all equal sides and angles. When you draw an altitude you have this:

You have a 30 - 60 - 90 triangle. The hypotenuse is always doubled the smallest side, the smallest side is half the hypotenuse and the longer side is square root of 3 times the the shorter side. Hence the hypotenuse is 10. Now you can find the perimeter.

23. Find the perimeter of the square. (The square has 13 square root 2)

Is this a diagonal or a side? Perimeter of a square is \(\displaystyle 4s\)

26. sin 74 degrees

27. tan 70 degrees

28. cos 49 degrees

If you are trying to find Sin? If so type the degree measurement in and press Sin .

29. x to the nearest degrees, where sin x ~~ 0.7202

30. y to the nearest degrees, where cos y ~~ 0.3880

Type in decimal number and press Inverse and then Sin.

 

[skeeter]

#37 ...

C = 90 ... indicates you're working with a right triangle.

angles A and B are complementary ... so, cosA = sinB = 1/3

sinB = opposite/hypotenuse = 1/3 ... adjacent side = sqrt(3² - 1²) = sqrt(8)

tanB = opposite/adjacent = 1/sqrt(8) = sqrt(8)/8 = 2sqrt(2)/8 = sqrt(2)/4

 

[Guest]

thanks
guys