题目 如图，点 $P$ 为矩形 $ABCD$ 内一点，$\angle PAB=20^\circ$，$\angle PBA=10^\circ$，$\angle APD=70^\circ$，则 $\angle BPC=$ <nn> </nn>．<br><img src="\static/images/1b9b1fc52ef3aa7d6b60ecd07c2546fb.png" class="img-responsive" /> 答案 $40^\circ$ 解析 <img src="http://bison.img.eduzhixin.com/math-img/9383e8ee7172af36d7893868608fddcf.png" class="img-responsive" /><img src="http://bison.img.eduzhixin.com/math-img/ed8e3607e7187d315ae1b7f8f5e39110.png" class="img-responsive" /> 备注