Lesson objective: Apply the Pythagorean Theorem to distance in 3D space.
This lesson provides an opportunity for students to apply their knowledge and understanding of calculating distance to a reallife situation. Students are asked to find the diagonal space in gift boxes to see if gifts with certain lengths will fit inside.
Key Concept students will use:
 We can use the relationships shown in the Pythagorean Theorem to solve problems given particular pieces of information about the problem.
Skills students will use:
 Use rational approximations of irrational numbers to compare the size of irrational numbers. (8.NS.A.2)
 Apply the Pythagorean Theorem to determine unknown side lengths in right triangles in realworld and mathematical problems in two and three dimensions. (8.G.B.7)

Apply the Pythagorean Theorem to find the distance between two points in a coordinate system. (8.G.B.8)
Students engage in Mathematical Practice 1 (make sense of problems and persevere in solving them) as they develop a strategy to find distance in three dimensions, then apply that strategy to see if the gifts will fit in the boxes.
Key vocabulary:
 3dimensional space
 diagonal
 Pythagorean Theorem