Question

已知角aoc,角bod都是直角,且角aob与角aod的度数之比是2;11,求角aob和角boc的度数

过程要详细，谢了啊

Answer 1

因为角aob与角aod的度数之比是2;11所以角aob与角bod的度数之比是2:9设角aob为x度，则x:90=2:9x=2090-20=70角aob为20度，角boc的度数为70

Answer 2

分两种情况讨论，(左边)∠aob:∠aod=2:11,设∠aob=x,则x:(x+90)2:11解得x=20°，∴∠aob=20°，∠boc=∠aoc+∠boa=20°+90°=110° (右边)∵∠aob:∠aod=2:11,设∠aob=x,则x:(90-x)=2:11解得x=180/13°∴∠aob=180/13°∠boc=∠aoc+∠boa=90+180/13°