PLS HELP WITH EIGHTH GRADE ALGEBRA

Solve with work adding cheese to a mcdonalds quarter pounder increases the fat content from 21g to 30g. what is the percent of change ?

Can someone me with these two circle theorem questions asap?

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.