SAT数学官方，每日一题6

>>SAT数学解析：SAT数学官方，每日一题6

Read the following SAT test question and then click on a button to select your answer.

If θ=330°, what is the value of θ in radians?

A.3/2π

B.5/3π

C.7/4π

D.11/6π

重点单词：

measure ['meʒə] n. 措施，办法，量度，尺寸

equation [i'kweiʃən] n. 相等，方程(式), 等式，均衡

factor ['fæktə] n. 因素，因子

circle ['sə:kl] n. 圈子，圆周，循环

multiple ['mʌltipl] adj. 许多，多种多样的

revolution [.revə'lu:ʃən] n. 革命，旋转，转数

conclude [kən'klu:d] vi. 总结，作出决定

conversion [kən'və:ʃən] n. 转变，改变信仰，换位

convert ['kɔnvə:t,kən'və:t] v. 变换，(使)转变，使 ... 改变信仰，倒置，兑换

答案：D

解析：

Recall that there are 2π radians in one revolution of a circle. There are also 360° in one revolution of a circle.

This leads us to the following conversion: 2πradians=360°

If we divide both sides by 360, we have 1°=π/180 radians.

We can use this factor to convert degrees to radians.

The conversion is performed below.

330°=330*1°=330*π/180=11π/6

Alternatively, if we divide both sides of the equation 2π radians=360° by 12, we can conclude that π/6 radians=30°.

Since 330° is 11*30°, its measure in radians must be 11*π/6.

Either way, we have the following: 330°=11π/6.

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