Mathematics Question and Solution
Shaded Area is;
Area quarter circle with radius 80 cm - Area triangle with height 80 cm and base 80 cm - Area quarter circle with radius 60 cm + Area triangle with height 60 cm and base 60 cm + Area quarter circle with radius 60 cm - Area triangle with height 60 cm and base 60 cm - Area sector with radius 40 cm + Area triangle with height 40 cm and base 40 cm.
= ¼(80*80π)-½(80*80)-¼(60*60π)+½(60*60)+¼(60*60π)-½(60*60)-¼(40*40π)+½(40*40)
= 1600π-3200-900π+1800+900π-1800-400π+800
= 1600π-3200-400π+800
= 1200π-2400
= 1200(π-2) cm²
