Lesson 12: Practice Problems

Problem 1

What is the surface area of this rectangular prism?

A rectangular prism showing faces with bases of 2 and 3 and a height of 4.

  1. 16 square units

  2. 32 square units

  3. 48 square units

  4. 64 square units

Problem 2

Which description can represent the surface area of this trunk?

A picture of an old trunk.

  1. The number of square inches that cover the top of the trunk.

  2. The number of square feet that cover all the outside faces of the trunk.

  3. The number of square inches of horizontal surface inside the trunk.

  4. The number of cubic feet that can be packed inside the trunk.

Problem 3

Which figure has a greater surface area?

Picture A has 5 blocks in the shape of an L. Picture B has 5 blocks in the shape of a an x

Problem 4

A rectangular prism is 4 units high, 2 units wide, and 6 units long. What is its surface area in square units? Explain or show your reasoning.

Problem 5 From Unit 1 Lesson 9

Draw an example of each of the following triangles on the grid.

  • A right triangle with an area of 6 square units.

  • An acute triangle with an area of 6 square units.

  • An obtuse triangle with an area of 6 square units.

blank grid

Problem 6 From Unit 1 Lesson 10

Find the area of triangle in square units. Show your reasoning.

A triangle with vertices labeled M, Q, and P. Triangle MQP is enclosed in a rectangle MRPN. Sides MR and PN of the rectangle are six units high, and sides RP and MN of the rectangle are 10 units long. Vertex Q is five units across side RP, and vertex O is 2 units down on side PN.

Problem 7 From Unit 1 Lesson 3

Find the area of this shape. Show your reasoning.

A four-sided shape on a grid, with two sides that drop 5 units as they cross 5 units and meet at a right angle, and two sides that drop two units as they cross 5 units.