vbd391t的部落格

標題:

3D Problem

發問:

ABCDV is rectangular based right pyramid with V as the vertex and ABCD as the base. AB = 5 cm., BC = 10 cm. and V is 20 cm. above the base. Find angle between plane VAB and VBC. 更新: To : 麻辣 Please notice that the question asked for angle between PLANE VAB and PLANE VBC, NOT angle A and angle B, please calculate again, thanks.

最佳解答:

suggested solution: 圖片參考：http://imgcld.yimg.com/8/n/HA08446686/o/20130326214404.jpg

• 請問2009年邊間大學有得讀~工商管理高級文憑~兼讀制呢@1@
• 請問以下文章是什麼文字-@1@
• 有關AB捐血問題

此文章來自奇摩知識+如有不便請留言告知

其他解答:

ABCDV is rectangular based right pyramid with V as the vertex and ABCD as the base. AB=5cm, BC=10cm and OV=20cm above the base. Find angle between plane VAB and VBC.O=(AC∩BD)=Intersecting point for AC & BDOA=OB=OC=OD=√(25+100)/2=5√5/2ΔVOA: VA^2=OV^2+OA^2=400+125/4=1725/4=> VA=VB=5√69/2ΔVAB cosine law: VA=VB=5√69/2, AB=5cosA=cosB=(1725/4+25-1725/4)/(2*5*5√69/2)=25*2/250√69=1/√69A=B=acos(1/√69)=83.0856(deg)......ans