I don’t even know how to start the problem. Can someone help?

Δabc is dilated by a scale factor of 3 with the origin as the center of dilation to form δa′b′c′. the slope of is -1.2. the length of is p units, the length of is q units, and the length of is r units. the slope of is . the length of is units.

What is the difference between the predicted value and the actual value

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class