五千年(敝帚自珍)

主题:【求解】儿子的数学题,10年级,我不会。 -- 李侠东

共:💬15 🌺14
全看分页树展 · 主题
家园 【求解】儿子的数学题,10年级,我不会。

脸红,来此请教,多谢。

A semi-circle of radius 8 cm, rocks back and forth along a line. The distance between the line on which the semi-circle sits and the line above is 12 cm, As it rocks without slipping, the semi-circle touches the line above at two points. ( When the semi-circle hits the line above it immediately rocks back in the other directions). The distance between these two points, in millimetres, is closest to (A) 55 (B) 53 (C)51 (D) 49 (E) 47

点看全图

全看分页树展 · 主题


有趣有益,互惠互利;开阔视野,博采众长。
虚拟的网络,真实的人。天南地北客,相逢皆朋友

Copyright © cchere 西西河