Question

Find the perimeter of a rectangle if three of its corners are (2.5,1.7), (2.5,-3.2), and (-0.7,-3.2).

Answer 1

Use the distance formula for each side:
\[d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\]
i.e. for one side you would compute:
\[d=\sqrt{(2.5-2.5)^2+(1.7+3.2)^2}\]

Answer 2

oops, I read triangle sorry. For a rectangle you can find the gradient of one of the missing sides as it will be the same (since it's parallel) as the side opposite it. Then you can use the formula:
\[y-y_1=m(x-x_1)\]
to find the equation of the line.
Do the same for the other missing side, then you can make the equations equal to each other to find the x (or y) value of the missing point. Then plus this into one of the two equations you found to find the y value (or x value). Then you can use the distance formula for each side.

Answer 3

*plug, not plus.

Answer 4

See pic attached.

U can see by eye that the width and height are 3.2 (on the x) and 4.9 (on the y)

So the perimeter is twice sum of these or 16.2.