This chapter focuses on the practical applications of definite integrals, highlighting their importance in solving real-world problems. Students will learn how to use definite integrals to calculate areas, volumes, and other geometric properties. They will also explore the use of integrals in determining the work done by a variable force, the arc length of a curve, and the center of mass of a planar region. By engaging with these applications, students will develop a deeper appreciation for the versatility and power of integral calculus in various fields, including physics, engineering, and economics.