Knowing that A 1ACC 1 is a parallelogram, then a 1c 1∨. Communication,
So ≈B 1CA is the angle formed by non-planar straight line b 1C and a1 -(2 points)
In △B 1CA, AC = 42, ab 1 = b 1c = 45,
Then cos ∠ ACB1= ac2+b1C2? AB 122AC？ B 1C= 10 10，
So ∠ ACB1= arccos1010. -(4 points)
(2) If students can ask some high-quality questions, they will be given (3 points) and those with answers will be given (5 points).
And asking some questions of little value will not give points.
If the question is in the following two situations, you can give points accordingly.
The first kind:
Problem: it is proved that the volume of triangular pyramid E-B 1BC is unchanged. -(3 points)
The problem is as shown in the figure. Because the distance from any point on DD 1∑ plane B 1bc 1 d to plane B 1bc 1 is equal, the triangular pyramid E-B 1BC and the triangular pyramid d-b. B 1BC=VD？ BC 1 year. -(3 points)
And VD? B 1BC= = I praised it and stepped on it. What's your comment on this answer? Put away comments//high quality or satisfaction or special types or recommended answers dottimewindow.iperformance & window.iperformance.mark ('c _ best',+newdate); Lawyer recommendation service: If your problem has not been solved, please describe your problem in detail and provide free professional consultation through Baidu Law Professional Edition. Other similar problems 2022-06- 18 are known as regular quadrangular prism ABCD-a1b1c1d1,where AA 1=2AB. 20 1 2-02-13 (1/2) As shown in the figure, it is known that ABCD-A1b1c1d1is a regular quadrangular prism with sides. Intravenous ... 620 16-08-26(20 14? As shown in the figure, in the straight triangular prism ABC-a1b1,∠ BAC = 90, AB = AC = AA 1. If d is the midpoint of B 1C 1, find the straight line AD20658. Shanghai) as shown in the figure, in the regular triangular prism ABC-a1b1c1,AA 1=6, and the angle formed by the non-planar straight line BC 1 and AA 1 is π6, so find the 422 of this triangular prism. In the cube a1b1c1d1-ABCD, the side length is a, and find the angle132012-013. 72010-12-21As shown in the figure, regular quadrangular prism ABCD-a1b1c1diagonal BD 1, BD/kloc-0. ① Find the angle formed by BD 1 and bottom ABCD 220 16-03-27 (20 14? Shanghai simulation) in the prism ABC-a 1 b1,∠ ABC = 90, AB=BC= 1, BB 1=2, find: (/kloc-0. & gt recommended for you: F.context('cmsRight', [{'URL':'/d01373f082025aaf511aa256e9edab64034f1a07? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId':'A24KA00562 '，}，{ ' URL ':/s？ word = % E6 % AC % A7 % E6 % B4 % B2 % E6 % 9D % AF & sa = searchpromo _ ozb _ zhidao _ tuijian '，' src ':'/3 BF 33 a 87 e 950352 AAF 5 df 4954 143 fbf2b 2 1 18 b6b？ x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId ':' '，}])； Is Huaqiang North's second-hand mobile phone reliable? Why is the cost of cancer treatment getting higher and higher? What impact will the "network toilet" have? The price of electric cars has dropped many times. Is the quality guaranteed? I recommend f.context ('recbrand', [{"img": "\/86D6277F9E2F07083523F69DFB 24B 899A901F20d? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto "，" url":"/hm.js？ 6859 ce 5a af 00 FB 00387 e 6434 E4 FCC 925 "； var s = document . getelementsbytagname(" script ")[0]； s.parentNode.insertBefore(hm，s)； })(); window . TT = 1720 100430；