trigonometry

please check my answers.
1.Find the area of the sector of a circle.
r=11.8cm, theta-pi/7 radians
I got 31.2cmsquared
2.Find the radius of a circle in which a central angle of pi/6radian determines a sector of area 76square meters.
I got 17.03m
3.Find the measure(in radians) of a central angle of a sector of area 45 square inches in a circle of radius 8 inches.
I need help getting the answer
4.In this question you're suppose to approximate the length by finding the necessary arc length.

A tree 520m away subtends an angle of 4degrees. find the height of the tree.
I also need help on this one
THANKS ALOT

  1. 0
  2. 6
asked by y912f
  1. 1. 31.24 yes
    2.17.04 yes
    3. total area = pi r^2 = pi(64)
    angle/2pi =45/64 pi
    angle = 45/32 = 1.41 radians = 80.6 degrees
    4. r = 520
    circumference = 2 pi (520) = 3267
    4/360 = height/3267
    height = 36.3

    1. 0
    posted by Damon
  2. Thanks so much; This was of great help!
    =D

    1. 0
    posted by y912f

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