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Home > INT1 > Chapter 6 > Lesson 6.4.2 > Problem 6-139


Plot on graph paper with points , , and .  

  1. Rotate the triangle counterclockwise () about the origin. Name the coordinates of the vertices of .

    Use the eTool to complete the transformation. Notice how the points have changed. Pay attention closely to point .
    Notice that the -coordinate has been multiplied by and the - and -coordinates are interchanged.

  2. Next, reflect across the -axis. Name the coordinates of the vertices of  .

    Use the eTool. Notice how the coordinates compare to the coordinates of . What happens to the points when you reflect across the -axis?

    , ,

  3. What is the area of ?

    What is the length of the base, ? What is the height from point to base ? Use the area formula for triangles.

Use the eTool below to solve the problem.
Click the link at right for the full version of the eTool: 6-139 HW eTool