Need help plz its math

Find the arc length of the semicircle. 7the grade

Last month, leonhard euler's watch kiosk at the mall had total sales of $9,489. merchandise totaling $225 was returned. the goods that were sold cost leonhard euler's $5,481. operating expenses for the moth were $992. what was the gross profit on sales?

Anew obstacle course is home to several new types of challenging obstacles. one such obstacle is traversing a 15-stair staircase. to make it more challenging, the stairs are not uniformly spaced. rather, the vertical space between consecutive stairs for the first 10 stairs is 113 feet and the vertical space for the last 5 stairs is 134 feet. what is the total vertical distance traveled ascending and descending the entire 15-stair staircase?