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# Confused!

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Please help! I've been stuck on these for a while. I am not good at trig so I am having a difficult time. Sorry! Thank you.

Sep 20, 2018

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a) In this one, we know an adjacent side to the angle and we are trying to find the opposite side....the tangent is the logical choice for this because  it relates the opposite side to the adjacent side...so we have

tan (30)  = x / 7

1/√3  = x / 7       multiply  both sides by 7

7 * 1 / √3  =  x  ≈  4.04   = 4 [ to the nearest tenth]

b) The volume of the tank  = L * W * H  = 30 cm * 24 cm * 15 cm  = 10800 cm^3  =  10800 g

Ther are 1000g in one kilogram, so...to find the water weight we have

10800 g  *     1 kg / 1000g       (cancel the grams)

10800 * 1 kg / 1000  =    18 kg  = water weight

c)  The  volume of this prism is  the area of the equilateral triangle forming the left  "face"  times the length of the prism=  (21 yd)

Area of the equilateral  triangle   =  (1/2) 15^2  (√3 / 2 )  =  225√3/ 4  yds^2

Volume =   225√3/ 4 * (21)  ≈  2046 yds^3

Sep 20, 2018