事故发生后,警方在两公里半径内设置了临时封锁线。Shìgù fāshēng hòu, jǐngfāng zài liǎng gōnglǐ bànjìng nèi shèzhì le línshí fēngsuǒxiàn.After the accident, the police set up a temporary cordon within a two-kilometre radius.
圆的半径是五厘米,请算一下它的面积。Yuán de bànjìng shì wǔ límǐ, qǐng suàn yíxià tā de miànjī.The radius of the circle is five centimetres; please work out its area.
以学校为中心,半径一公里内有三家书店。Yǐ xuéxiào wéi zhōngxīn, bànjìng yì gōnglǐ nèi yǒu sān jiā shūdiàn.Within a one-kilometre radius of the school there are three bookshops.