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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 translate 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