Find area of triangle(in Cartesian plane) with vertices (0,7),(-4,5),(-4,-2)

Question

My answer is not matching. I got 16 units sq. 

Answer 1

It really, really helps to plot the triangle (note: WyzAnt Answers Forum makes that difficult).

 

Here are the points:

 

                                 |

                                 *

                                 |

                                 |

                   *            |

                                 |

                                 |

                                 |

   - - - - - - - - - - - - - - - - - - - - - - - - -

                                 |

                    *           |

                                 |

 

Then, recall the formula for the area of a triangle:

       A = (1/2)bh

         where the base and the height are perpendicular line segments

 

The vertical line segment makes measuring a horizontal (that is, perpendicular) distance pretty easy.  So,

      b = ( 5 - (-2)) = 7

      h = (0 - (-4)) = 4

 

A = (1/2)*7*4

A = 14 square units