Hippocrates of Chios solved this, nearly 100 years before Euclid even wrote The Elements, and before we knew the exact formula for the area of a circle. This is said to be the first precise mathematical of the area between two curved lines. Learn how he solved for the area of a crescent-shaped lune (same Latin root as luna for moon). And I hope this will inspire you to solve a problem today that students thousands of years from now will learn in grade school.