If A = 18degrees, b - a =2, ab =4, using the usual notation fora triangle, use the sine rule to find B.

Help I keep getting this q wrong in my book it says the answer is 53.85, but i keep getting like 53.999.

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- Dec 16th 2009, 01:36 PMDetanonSine Rule q
If A = 18degrees, b - a =2, ab =4, using the usual notation fora triangle, use the sine rule to find B.

Help I keep getting this q wrong in my book it says the answer is 53.85, but i keep getting like 53.999. - Dec 16th 2009, 01:42 PMe^(i*pi)
Solve the simultaneous equations for a and b

$\displaystyle a = -1+ \sqrt{5}$ : $\displaystyle b = 1+\sqrt{5}$

$\displaystyle \frac{sinA}{a} = \frac{sinB}{b}$

$\displaystyle B = arcsin \left(\frac{b}{a}sinA\right) = arcsin \left(\frac{1+\sqrt5}{1-\sqrt5}sin(18)\right) = $

How odd, I get -54 exactly - Dec 16th 2009, 05:25 PMKrahl
i get exactly 54.

but thats without rounding. and the book is way off.