Trên một khu đất hình chữ nhật rộng 40m , dài 45m người ta đắp một nền nhà diện tích 64m2 và làm một vườn hoa hình tròn bán kính 4m . Xung quanh vườn hoa người ta làm một lối đi rộng 2m. Tính :
a) Diện tích lối đi ?
b) Diện tích đất còn lại ?
giúp mick với
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