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August 6th, 2019, 02:17 PM  #1 
Newbie Joined: Aug 2019 From: South Africa Posts: 8 Thanks: 0  How do I calculate missing side and angles of this trapezoid?
Hi there. I've been trying to figure out how to calculate side bc of the trapezoid I've attached to this post. Side ab = 28.693, side ad = 612.651 and side dc = 31.7705. Angle c = 90 degrees and angle b is equal to 90 degrees. How on earth does one go about calculating the length of side bc and it's angle in relation to ad and then how does one also go about calculating what angles d and a are ? Please help Kind regards Edwin 
August 6th, 2019, 02:55 PM  #2 
Math Team Joined: Jul 2011 From: Texas Posts: 3,002 Thanks: 1587 
$\cos{d} = \dfrac{31.770528.693}{612.651}$ you should be able to figure it all out from here Last edited by skeeter; August 6th, 2019 at 02:57 PM. 
August 7th, 2019, 02:20 AM  #3 
Newbie Joined: Aug 2019 From: South Africa Posts: 8 Thanks: 0 
Hi there Skeeter, thank you for helping me once more. Could you please confirm for me if this is correct ? cos d = (31.7705−28.693)÷612.651 d = arccos(3.0775÷612.651) d = 89.712 degrees bc = 612.651×sin89.712 bc = 612.643 Kind regards Edwin 
August 7th, 2019, 05:56 AM  #4 
Math Team Joined: Jul 2011 From: Texas Posts: 3,002 Thanks: 1587  
August 7th, 2019, 06:37 AM  #5 
Newbie Joined: Aug 2019 From: South Africa Posts: 8 Thanks: 0 
Thank you Skeeter, much appreciated.


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angles, calculate, missing, side, trapezoid 
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