a circular ground whose diameter is 70 metres , has a 2.8 metre - broad garden around it . what is the area of the garden in square metres ?
"req . area = ï € [ ( 37.8 ) 2 â € “ ( 35 ) 2 ] = 22 â  „ 7 ã — ( 72.8 ã — 2.8 ) [ since a 2 - b 2 = ( a + b ) ( a - b ) ] = 22 ã — 72.8 ã — 0.4 = 640.64 sq m answer c"
subtract(circle_area(add(divide(70, const_2), 2.8)), circle_area(divide(70, 2.8)))