agree on, agree to, agree with

Agree on means to share the same opinion about items, topics or standards:

• All parties agreed on plans to expand the Rideau Centre.

Agree to means to commit to (a course of action, a proposal, etc.):

• Ontario’s ruling Conservatives and opposition Liberals agreed to adopt new rules that allow the NDP to qualify for official party status.

• The manager agreed to the recommendation submitted by the working group.

Agree with means to have the same opinion as another person or to approve of something.

• I agree with you that spaghetti sauce can never have too much garlic.
• I agreed with the approach Mike adopted.

In addition, facts may agree with (correspond to) each other.

• Your data do not agree with our results.