Mike (often) goes on a field trip to procure some required parts.

Though no formal classes are offered during eighth period, it is a required part of a school day.

This interview is a required part of the nomination process and will take place in late fall.

This year, media studies became a required part of the national curriculum in Britain.

In junior high school or its equivalent, music usually continues to be a required part of the curriculum.

My friend asked me to help her choose a photograph, a required part of a job application.

By 1891, manual training was a required part of public school education.

"It's voluntary now, but we envision it becoming a required part of the first year."

Bird wished to free his hands to better apply the electricity to the required part of the patient.

You can say it's a required part of your investigation.