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正方体ABCD-A1B1C1D1中,O是上底面ABCD中心,若棱长为a,则三棱锥O-AB1D1的体积为.

题目详情
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答案和解析
作业帮 如图,在正方体ABCD-A11B11C11D11中,
O是上底面ABCD的中心,棱长为a,
∴对角线AC⊥平面BDD11B11,
∴三棱锥O-AB11D11的体积为
V三棱锥O-AB1D1=
1
3
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
V三棱锥O-AB1D1=
1
3
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
三棱锥O-AB1D1=
1
3
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1D1=
1
3
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1=
1
3
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1
3
111333•S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
S△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
△OB1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1D1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1•AO
=
1
3
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1
3
111333•
1
2
B1D1•OO1•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1
2
111222B11D11•OO11•AO
=
1
3
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1
3
111333•
1
2
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
1
2
111222•
2
a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
2
2
22a•a•
2
2
a
=
1
6
a3.
故答案为:
1
6
a3.
2
2
2
2
2
2
22222a
=
1
6
a3.
故答案为:
1
6
a3.
1
6
111666a3.
故答案为:
1
6
a3.
3.
故答案为:
1
6
a3.
1
6
111666a3. 3.