Learn on PengienVision, Mathematics, Grade 6Chapter 7: Solve Area, Surface Area, and Volume Problems

Lesson 2: Solve Triangle Area Problems

In this Grade 6 lesson from enVision Mathematics Chapter 7, students apply the triangle area formula A = ½bh to find the areas of various triangles, including right triangles and triangles plotted on a coordinate plane. Students practice identifying the base and height, working with mixed units, and reasoning about how to reverse the formula to solve for an unknown base or height.

Section 1

Area of Triangles

Property

The area of a triangle is one-half the base, bb, times the height, hh.

A=12bhA = \frac{1}{2}bh

Examples

Section 2

Identifying the Height of a Triangle

Property

For any triangle with area A=bh2A = \frac{bh}{2}, the altitude hh is drawn perpendicular to the base bb.
In acute triangles, the altitude falls inside the triangle.
In obtuse triangles, the altitude to the longest side falls outside the triangle and must be drawn to the extension of the base.

Examples

Book overview

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Chapter 7: Solve Area, Surface Area, and Volume Problems

  1. Lesson 1

    Lesson 1: Find Areas of Parallelograms and Rhombuses

  2. Lesson 2Current

    Lesson 2: Solve Triangle Area Problems

  3. Lesson 3

    Lesson 3: Find Areas of Trapezoids and Kites

  4. Lesson 4

    Lesson 4: Find Areas of Polygons

  5. Lesson 5

    Lesson 5: Represent Solid Figures Using Nets

  6. Lesson 6

    Lesson 6: Find Surface Areas of Prisms

  7. Lesson 7

    Lesson 7: Find Surface Areas of Pyramids

  8. Lesson 8

    Lesson 8: Find Volume with Fractional Edge Lengths

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Area of Triangles

Property

The area of a triangle is one-half the base, bb, times the height, hh.

A=12bhA = \frac{1}{2}bh

Examples

Section 2

Identifying the Height of a Triangle

Property

For any triangle with area A=bh2A = \frac{bh}{2}, the altitude hh is drawn perpendicular to the base bb.
In acute triangles, the altitude falls inside the triangle.
In obtuse triangles, the altitude to the longest side falls outside the triangle and must be drawn to the extension of the base.

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 7: Solve Area, Surface Area, and Volume Problems

  1. Lesson 1

    Lesson 1: Find Areas of Parallelograms and Rhombuses

  2. Lesson 2Current

    Lesson 2: Solve Triangle Area Problems

  3. Lesson 3

    Lesson 3: Find Areas of Trapezoids and Kites

  4. Lesson 4

    Lesson 4: Find Areas of Polygons

  5. Lesson 5

    Lesson 5: Represent Solid Figures Using Nets

  6. Lesson 6

    Lesson 6: Find Surface Areas of Prisms

  7. Lesson 7

    Lesson 7: Find Surface Areas of Pyramids

  8. Lesson 8

    Lesson 8: Find Volume with Fractional Edge Lengths