Using estimation to solve real-life problems

can some one give me an math equation plss

Can someone check if i did this correct. it’s number 4 if you’re wondering.

How do you write something in scientific notation?

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.