Atown had about 2120 acres of pine tress 40 years ago. only about 13% of the pine tress remain. how many acres of pine tress remain?

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.