Answer:
25
Step-by-step explanation:
Each of the 16 "ratio units" representing all 80 dancers must stand for ...
(80 dancers)/(16) = 5 dancers
Then 5 "ratio units" representing seventh-grade dancers will stand for ...
5 × 5 dancers = 25 dancers
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Another way to figure this is to write the proportion ...
(seventh-grade dancers)/(all dancers) = 5/16
seventh-grade dancers = (all dancers)×(5/16) = 80×5/16
seventh-grade dancers = 25
150/4 = 37.5cm. You divide by four because there are four sides on a rectangle. But 37.5 is the cm of a square. Since it says one of the sides is 15cm greater, you subtract 37.5 - 15 = 27.5cm on 2 of the width. While the other 2 lengths are greater than the width by 15 cm, so you add 15 to 37.5 which gives you 52.5cm. So the 2 width are 27.5cm and the length is 52.5cm.
66.6% because 100 is 2/3rds of 150
