14 to 21= to 15 me find the ratio

This race was first held in 1953 on august 16th. every decade the race finishes with a festival. how many years is this?

How can i differentiate this equation?

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.