A) 31 degrees
b) 118 degrees
Oh wow. Uhm. Add all the sides together and that's the surface area?
Answer:
the difference of 2 times d minus 3= 6
4 added to the difference of d minus 3= 4
the difference of d minus 3 divided by 2= 0
the quotient of 12 divided by the difference of 3 times d minus 3= 2
Step-by-step explanation:
2 times 3 equals 6. 3 minus 3 equals 0. 6-0=6
d minus 3 equals 0. 4+0 equals 4
3 minus d equals 0. 0 divided by two is 0
3 times d= 9. minus 3 = 6. 12 divided by 6 = 2
hope this helps! (:
7 is incorrect. The answer should be -4. Here's how I'd derive it:

With
, we should expect
. If
, then

Also,

so we should expect
and

You seem to be taking

but this is not an identity.
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8 is incorrect. Just a silly mistake, you swapped the order of the terms in the numerator. It should be

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9. Use the identity from (7).
lies in the second quadrant, so

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12.




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13.




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14.



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15.


