tongxun

It is a present spry gave me. I really do not know its origion.
Maybe you could find it by asking spry through "brief messege".
Spry is a banzhu of this forum.

pgclt

tongxun, thanks for your words. I will certainly come back and help if I can. btw, the following two problems: 8、有图：矩形照片周围binder：照片长为宽两倍；binder每边距离矩形边都是2，binder面积196。求照片面积。 这题一开始我理解成binder是整个大矩形面积，浪费些时间，后来醒悟原来只是照片边上的框框。 (L-4)(W-4)=LW+196; L=2W -------------------------------- 公式应该是： 1）(L+4)(W+4)=LW+196; 2）L=2W ------------------- 我充忙中写错了。你的对。 =================================== 1、DS：what's the proximation integer value of (4a+10)/a 1) a>20 2) 10

tongxun

pgclt： 谢谢！真的，谢谢你！

    若有时间能回来帮助大家，我感激不尽！因为，咱们论坛中互相讨论的气氛太差了！也许是我没水平导致的。

cook

1、DS：what's the proximation integer value of (4a+10)/a 1) a>20 2) 10 I got 40Pai, why ? r=20

cook

what the different between answer 1 and 2 ? I can't understand, please advice! thanks!

pgclt

tongxun, 别客气。你对我的帮助还少吗！ cook, 我的思路是 (4a+10)/a => 4+(10/a) if a>20 => 4+(10/a) 小于4.5,大于4.0。四舍五入为4。充分。 if 104+(10/a) 小于5，大于4.1。可能为4或5。所以不充分。 7、 有图：一圆内chord与一半径垂直相交，chord长度为12， 半径在chord上那段长度为2，求圆周长 20pai -------------- chord 一半是6， (r-2)^2 + 6^2 = r^2 =>r=10.

cook

Got it , thank you very much! How can be very very careful!!!

Congrats for your triumph !