Surface Area of Rectangular Prisms Unit 4, Lesson 16
Today’s standard: CCSS. MATH. CONTENT. 7. G. B Today’s standard: CCSS.MATH.CONTENT.7.G.B.6 Solve real-world and mathematical problems involving area, volume and surface area of two- and three- dimensional objects composed of triangles, quadrilaterals, polygons, cubes, and right prisms. How will you prove you understand this topic? By scoring at least 75% (3 out of 4) on the exit ticket.
Surface area is the combined area of every side of a 3-D shape. Painting the outside of a 3-D object or wrapping it in paper would require knowing the surface area.
To calculate the surface area, find the area of each side by itself and add them together. A rectangular prism has 6 sides so you would find the area of and then add them together.
Example What is the surface area of this rectangular prism? Let’s start by finding the area of the front face.
Example Area of front: 3 cm x 5 cm = 15 cm² The back and front are equal so the back also = 15 cm² Next, let’s figure out the left/right sides
Example Area of right side: 4 cm x 5 cm = 20 cm² The left side is also 20 cm². Finally, let’s figure out the top/bottom
Example Area of bottom: 3 cm x 4 cm = 12 cm² The top is also 12 cm².
Surface area = 15 + 15 + 20 + 20 + 12 + 12 = 94 cm² Example front back right left bottom top Surface area = 15 + 15 + 20 + 20 + 12 + 12 = 94 cm² Surface area is units² even though it’s a 3-D shape because you are painting flat areas, not filling up the volume.
Find the surface area