In the figure below, AB is a straight line. ∠ a is 45˚ smaller than ∠ b. ∠ a is 30˚ greater than ∠ c. <br> What is the ratio of ∠ a : ∠ b : ∠ c? <br> <input min="0" type="number" id ="imp5pg202q9_1" class="lineinput" placeholder="?" /> : <input min="0" type="number" id ="imp5pg202q9_2" class="lineinput" placeholder="?" /> : <input min="0" type="number" id ="imp5pg202q9_3" class="lineinput" placeholder="?" />