<span>C) Ro 270 degree (anticlockwise)
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841 jumping jacks per 4 minutes

Divide both sides by 4.

Delilah can do 210.25 (or 210) jumping jacks per minute.
This is an impossible equation. If sqrt(x) = sqrt(x), and sqrt(x) + 2 = sqrt(x) + 12, then that would mean that 2=12, which is incorrect.