This document provides information on finding the areas of triangles, trapezoids, and rhombi. It gives the formulas for calculating the area of each shape, includes examples of applying the formulas, and provides practice problems for students to work through. The lesson plan is for a two-day unit covering adding the areas of different plane figures, with the first day focused on notes and examples, and the second day devoted to review and assessment.

1. Areas of Triangles, Trapezoids,
and Rhombi
Section 11.2

2. Areas of Triangles, Trapezoids, and
Rhombi
• How do I find the areas of triangles?
• How do I find the areas of trapezoids and
rhombi?

3. Area of a Triangle
•

4. Triangle Example
• Find the area

5. Area of a Trapezoid
•

6. Trapezoid Example
• Find the area

7. Area of a Rhombus
•

8. Rhombus Example
• Find the area

9. Example
• Find the area of quadrilateral ABCD if AC = 35,
BF = 18, and DE = 10.

10. Coordinate Plane Example
• Find the area of
trapezoid RSTU with
vertices R(4, 2), S(6, -1),
T(-2, -1), and U(-1, 2).

11. Coordinate Plane Example
• Find the area of
rhombus MNPR with
vertices at M(0, 1),
N(4, 2), P(3, -2), and
R(-1, -3).

12. Example
• Rhombus RSTU has
an area of 64 square
inches. Find US if
RT = 8 inches.

13. Example
• Trapezoid DEFG has
an area of 120 square
feet. Find the height
of DEFG.

14. Your Turn
1. Find the area of quadrilateral HIJK if IK =
16, HL = 5, and JM = 9.
2. Find the area of trapezoid WXYZ with
vertices W(-3, 0), X(1, 0), Y(2, -3), and Z(-5, -
3).
3. Trapezoid QRST has an area of 210 square
yards. Find the height of QRST.

15. Homework
• Page 606
▫ 16 - 20 Even
▫ 30 – 34 Even
▫ 40 – 44 Even

16. Lesson Plan
• Intro
▫ Adding area of triangles, trapezoids and rhombi
• Standards- 10.2
• Supplies – slides, whiteboard, note sheets
• Timing: One day for notes, one day for a combined
review of 10.1 and 10.2 followed by a quiz
• Day 1:
▫ Essential Questions- slides 2
▫ Input-slides 3, 5, 7
▫ Guided Practice - slides 4, 6, 8 - 14
▫ Independent Practice – bookwork