Question

What is the area of the triangle formed from (0,-1), (0.4), and (4,-1)?

Answer 1

Answer:

10 squared units

Step-by-step explanation:

This triangle is pretty easy since it creates a right triangle.  So the base length and height length are pretty easy to identify.

The area of a triangle is .5*base*height.

The base length after drawing the points is a horizontal so just count it or do 4-0=4.

The height length after drawing the points is a vertical so just count it or do 4-(-1)=4+1=5.

So the area of the triangle is .5*4*5=.5(20)=10 units squared.

Now if you didn't fill like drawing it and you knew how to find the determinant.

You just compute

.5 times det|  0   -1     1  |

                   |  0   4      1  |

                   |   4  -1      1  |

.5[  0 det| 4     1  |          -   -1 det|  0   1 |          +    1 det | 0   4 |      ]

              |  -1    1  |                        |  4   1 |                         |  4  -1 |

.5[ 0                           - -1(0-4)                      +   1(0-16)]

.5[  0                         -4                               -16]

.5[-20]

-10

And if you get a negative just take the absolute value of it giving you 10.