In this question, the speed of the dolphin is already given, but the unit is different. The speed of the dolphin is given as 40 miles per hour and it has to be converted to feet per hour.
We already know that 1 mile = 5280 feet
Then
40 mile = 5280 * 40 feet
= 211200 feet
So the speed in feet per hour will be 211200 feet per hour. I hope the procedure is clear enough for you to understand. You can always use this method for solving similar problems without requiring any help from outside.
According to above figure, the angles (8x - 20)° and (5x + 37)° are pairs of vertical opposite angles, so
If you are moving the center of circle 2 to the the center of circle 1, then the translation rule is (x,y) ---> (x+4, y+10).
Note how x = 1 turns into x = 5. So we add 4
Also, y = -2 turns into y = 8. We add 10
The scale factor to turn the radius r = 4 into r = 8 is 2. Basically we double the radius. We can divide the two radii to see 8/4 = 2
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Summary:
To go from circle 2 to circle 1, we apply these two transformations
translation: (x,y) ---> (x+4, y+10)
dilation: scale factor 2
note:
if you want to go backwards, go from circle 1 to circle 2, then undo the transformations above
