How to filter rows with respect to specific entry?

I have thousands of rows and I want to filter those rows in which the entry at third position is three

For example

A=[1 2 3 4 5 6 7 8 9;0 1 2 3 4 5 6 7 8 9 10;5 6 3 2 1 4 7 8 9];

I want the resulting matrix

AA=[1 2 3 4 5 6 7 8 9;5 6 3 2 1 4 7 8 9]

Thanks

[dpb]

>> A=[1 2 3 4 5 6 7 8 9;0 1 2 3 4 5 6 7 8 9 10;5 6 3 2 1 4 7 8 9];
Dimensions of matrices being concatenated are not consistent. 
>>

Answer 1

[dpb]

>> A=[1 2 3 4 5;0 1 2 3 4;5 6 3 2 1];
>> A(A(:,3)==3,:)
ans =
     1     2     3     4     5
     5     6     3     2     1
>>

[Ammy]

Thanks