Back to Use distance formula for area — Problem 3 · Task Set 32

Exercises: Compute Perimeters and Areas Using Coordinates

Show all work for each problem. Express exact answers using radical form unless a decimal approximation is requested. Label every answer with correct units.

Grade 10·20 problems·~30 min·Common Core Math - HS Geometry·standard·hsg-gpe-b-7

Work through problems with immediate feedback

Fluency Practice

Apply the distance formula and area formulas to each figure.

Triangle $DEF$ has vertices $D(1, 1)$ , $E(5, 1)$ , and $F(3, 4)$ .
A student says the perimeter is $4 + \sqrt{13}$ units.
What error did the student make, and what is the correct perimeter?

The student forgot side $FD$ . The correct perimeter is $4 + 2\sqrt{13}$ units.

The student computed $DE$ incorrectly. The correct perimeter is $4 + 2\sqrt{13}$ units
but for a different reason.

The student used the wrong formula. The correct perimeter is $4 + \sqrt{13}$ units.

No error was made; $4 + \sqrt{13}$ is correct.