# Triangles and Coordinate Proofs

#### Gretski

##### New member
My problem says, "isosceles ABC with base AB that is a units long," and the instructions that go with it are, "Position and label each triangle on the coordinate plane." I am confused on how to put this on a coordinate plane. Where? I keep seeing different things for different triangles. Does it matter? What does it mean a units long? I have tried looking in the book, but it has not yielded any helpful information. Thanks.

#### lev888

##### Senior Member
My problem says, "isosceles ABC with base AB that is a units long," and the instructions that go with it are, "Position and label each triangle on the coordinate plane." I am confused on how to put this on a coordinate plane. Where? I keep seeing different things for different triangles. Does it matter? What does it mean a units long? I have tried looking in the book, but it has not yielded any helpful information. Thanks.
Please post a photo of the problem.

#### HallsofIvy

##### Elite Member
Since the problem doesn't say where on the coordinate plane, I would position the base of the isosceles triangle from (0, 0) to (a, 0). If there is no further information, the third vertex would be at (a/2, h) where h is the height of the triangle.

The choices of (0, 0) as one vertex and the base lying on the x-axis are of course arbitrary.