What is the measure of angle a in the triangle below?

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

Barney & noblet customers can choose to purchase a membership for $25 per year members receive 10% off all store purchases 1. how much would a member pay per year if he bought $50 worth of items each year? 2. write a slope-intercept equation that expresses how much a member pays per year using x to represent his purchases per year 3. how much would a member have to spend per year to pay off his membership fee?

What is r i 4.5+10r=-6.5 with work pls