Question

Figure ABCD is graphed on a coordinate plane.

ABCD is an isosceles trapezoid. What is the approximate perimeter of ABCD? Round to the nearest tenth.

16.5 units
18.9 units
20.9 units
24.0 units

Answer 1

20.9 Is your answer

Answer 2

1. BC is 1+3=4 (units)

2. AD is 3+5= 8 (units)

3. Draw the altitude CH from point C, as shown in the figure.

4. Then triangle CHD is a right triangle, with hypothenuse CD, and sides HD and CH.

5.
`CD^2=HD^2+CH^2`


`CD^2=2^2+4^2=4+16=20`


`CD= √(20)= √(4*5)= √(4) * √(5)=2 √(5)= 4.47`

6. AB=CD=4.47 because the trapezoid is isosceles.

7. P= BC+AD+AB+CD=4+8+4.47+4.47=20.9 (units)