Grade 6 Mathematics · Unit 5: Solve Area, Surface Area, and Volume ProblemsStandard 6.GR.1

Lesson 5.25.2 Small Group · Group 2

Group 2 · Set BSecond challenge form · new problems, same idea

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can find the area of a triangle using the formula A = ½ × base × height, explain why the method works, and use it on a problem I have not seen before.

Remember5.2 Small Group · Group 2

The height of a triangle meets the base line at a square corner, even outside the shape, and doubling the area undoes the half. The height always meets the base line at a square corner. Sometimes it is outside the triangle.

Words: Base (Base)Height (Altura)Area (Área)Perpendicular (Perpendicular)Composite figure (Figura compuesta)

  1. 1Complete each step, then write the final answer.

    A triangle has an area of 24 square centimeters. Its height is 6 cm. How long is its base?

    Show your work
    Final answer:
  2. 2Complete each step, then write the final answer.

    A triangle has an area of 54 square feet. Its base is 12 feet. What is its height?

    Show your work
    Final answer:
  3. 3Complete each step, then write the final answer.

    The front of a cabin is a triangle 20 feet wide at the bottom and 15 feet tall. One can of paint covers 50 square feet. How many cans cover the front?

    Show your work
    Final answer:
  4. 4Complete each step, then write the final answer.

    A right triangle has short sides of 9 cm and 12 cm. Its long side is 15 cm. What is the height from the square corner to the 15 cm side?

    Show your work
    Final answer:

Explain your thinkingSometimes the height of a triangle falls outside the triangle. How do you find it, and why is it still the height?

How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help