展览馆门前的圆形水池周长是78.5米，它的直径是多少米？半径是多少米?5c;I8{9g1l9H'I.z'P'^1`)N
解：
算式：提示0o5A:?)~2a3L;~7s9h5c;I8{9g1l9H'I.z'P'^1`)N
答：它的直径是*a.r*r*e*W1r3h5]/|米，半径是7F-U4O7u1X+I4Y([8p*^2A7S米。5c;I8{9g1l9H'I.z'P'^1`)N