3 sentences

1. 他的疲劳已经达到了极点。

   tā de pí​láo yǐ​jīng dá​dào le jí​diǎn.

   His exhaustion has reached its limit.

   Source: Dong Chinese Dictionary

2. 今天我的心情坏到了极点。

   jīn​tiān wǒ de xīn​qíng huài dào le jí​diǎn.

   I'm in a really bad mood today.

   Source: OpenSubtitles

3. 在极坐标系中，极点通常用字母O来表示。

   zài jí​zuò​biāo​xì zhōng, jí​diǎn tōng​cháng yòng zì​mǔO lái biǎo​shì.

   In a polar coordinate system, the pole is usually represented by the letter O.

   Source: Dong Chinese Dictionary