The internal \(d_i\) and external \(d_o\) diameters of a Shelby sampler are 48 mm and 52 mm, respectively. The area ratio (\(A_r\)) of the sampler (in %, round off to two decimal places) is _______________
Rearrange the following parts to form a meaningful and grammatically correct sentence:
P. a healthy diet and regular exercise
Q. are important habits
R. that help maintain good physical and mental health
S. especially in today's busy world