Cook pasta according to package instructions, then rinse under cold water.

In a large bowl, combine pasta, tomatoes, cucumber, onion, bell peppers, and feta.

In a separate bowl, whisk together Greek yogurt, olive oil, lemon juice, garlic powder, salt, and pepper.

Pour dressing over the salad and toss until everything is well coated.

Chill for at least 30 minutes before serving.