Question

Find the perimeter of the following shape rounded to the nearest tenth

A (-3,5) B (1,7) C (3,3) D (-1,1)

Answer 1

You can use the "distance formula" which is a result of the Pythagorean Theorem to find the distance between all of the points which will be equal to the perimeter.

d^2=(x2-x1)^2+(y2-y1)^2 so

AB^2=(7-5)^2+(1--3)^2=2^2+4^2=20

BC^2=(3-7)^2+(3-1)^2=(-4)^2+2^2=20

CD^2=(1-3)^2+(-1-3)^2=(-2)^2+(-4)^2=20

DA^2=(1-5)^2+(-1--3)^2=(-4)^2+2^2=20

So the perimeter is AB+BC+CD+DA which is:

P=√20+√20+√20+√20

P=4√20

P=4√(4*5)

P=8√5 units

P≈17.89 units (to nearest hundredth of a unit)