Answer:
90°
Step-by-step explanation:
[tex]Sum\:of\:angles\:= 540\°\\\\b + (b+45)+90+(2b-90)+\frac{3}{2}b =540 \\\\Expand\: the \: brackets \\b\°+b\°+45\°+90+2b\°-90\°+\frac{3}{2} b=540\\\\Collect \:like\:terms\:and\:simplify\\b\°+b\°+2b\°+\frac{3}{2} b +45+90-90\°=540\°\\\\4b\° + \frac{3}{2} b\° +45\° = 540\°\\\\\frac{11}{2} b = 540\°-45\°\\\frac{11b}{2} = \frac{495}{1}\\ Cross\:Multiply\\11b = 49\°5\times 2\\11b = 990\°\\Divide \:both\:sides\:of\:the\:equation\:by \:11\\\frac{11b}{11} = \frac{990}{11}\\ \\b = 90\°[/tex]
