The least populous state, Wyoming, has a population of apx. 500,000 and has one Representative in the House.
The most populous state, California, has a population of over 35,000,000 and has 53 Representatives in the House.
If California's representation were proportional relative to Wyoming, it would have 70 Representatives.
All of the states with larger populations are similarly under-represented.
Adding 75 Seats to the House, distributed according to existing formulas, would be a simple way to partially alleviate this imbalance.