宜昌市曾命制一道数学中考试题(课改实验区)如下:如图1,某一时刻太阳光从教室窗户射入室内,与地面的夹角∠BPC为30°,窗户的一部分在教室地面 Yichang City once made a mathematics test question (reform the experimental area) as follows: As shown in Figure 1, at some point, sunlight was injected into the room through the classroom window, and the angle between the ground and the ground was 30°. Part of the window was in the classroom floor.