In the right triangle, the longest side is the hypotenuse. Let α be the angle opposite to the side with a length of 12 units, <span>then according to the Law of sines:
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In a triangle, the three interior angles always add to 180° ⇒
To get the answer we have to substitute b=3 and solve it. 5a-10b=45 5a-10*3=45 5a-30=45 /+30 add 30 both sides 5a-30+30=45+30 5a=75 /:5 divide both sides by 5 5a:5=75:5 a=15 - its the answer