Similar Circles

Circle A has center (2, 7) and radius 2. Circle B has center (9, 1) and radius 5. Which transformations can be used to show that the two circles are similar?

• Translate circle A right 7 and down 6 and then dilate with scale factor 5/2 and center (9, 1)

• Translate circle A left 7, up 6 and then dilate with scale factor 2/5 and center (9, 1).

• Dilate circle A using center (2, 7) and scale factor 2/5 then translate right 7 and down 6

• Reflect circle A over x = 5.5 and translate up 6 units.

Tags

CCSS.8.G.A.4

CCSS.HSG.SRT.A.2

What transformations can be used to show circles I and J are similar?

• Dilate circle I about (4, 11) with scale factor 1/3 and then translate down 4 and left 7.

• Translate circle J right 4 and up 7 and then dilate about point (4, 11) with a scale factor 1/3

• Translate circle J left 7 and down 4 and then dilate about point (4, 11) with scale factor 3.

• Dilate circle I about (4, 11) with scale factor 1/3 and then translate left 4 and down 7.

Circles X and Y have a similarity ratio of 1/2. Which of the following could NOT be true about the circles?

• Circle X has a radius of 5 while Circle Y has a radius of 10.

• Circle X has a circumference of 15π and Circle Y has a circumference of 30π.

• Circle X has a radius of 12 while Circle Y has a radius of 6.

• Circle X has a circumference of 60π while Circle Y has a circumference of 20π.

Proving which pair of circles to be similar would involve a scale factor of 2 and a translation of right 10 and down 2?

• Circle L to Circle M

• Circle K to Circle L

• Circle K to Circle M

• Circle N to Circle L

Circle B is mapped to Circle D using a dilation with center (1, -7) and scale factor 3/5 followed by a translation right 2 and up 6. If the radius of Circle B is 15 units, describe Circle D.

• Circle D has a radius of 9 and center (3, -1).

• Circle D has a radius of 3 and center (-1, -13).

• Circle D has a radius of 25 and center (3, -1).

• Circle D has a radius of 12 and center (-1, -13).