According to my visual inspection, this obtuse angle should have almost 120 degrees.
Examples (Wiktionary)
Mandarin
他在学堂的时候,先生问他:“直隶省的西边是哪一省?”他说是陕西。先生说:“错了,是山西,不是陕西。”他说:“陕西同山西,不是差不多吗?”
他在學堂的時候,先生問他:“直隸省的西邊是哪一省?”他説是陝西。先生説:“錯了,是山西,不是陝西。”他説:“陝西同山西,不是差不多嗎?”
tā zài xué táng de shí hòu , xiān shēng wèn tā : “ zhí lì shěng de xī biān shì nǎ yī shěng ? ” tā shuō shì shǎn xī . xiān shēng shuō : “ cuò le , shì shān xī , bù shì shǎn xī . ” tā shuō : “ shǎn xī tóng shān xī , bù shì chā bù duō ma ? ”
When he went to school, the teacher asked him: "Which province is west of Zhili Province?" He answered Shaanxi. The teacher said: "Wrong, it is Shanxi, not Shaanxi." He said: "Would Shaanxi and Shanxi not be close enough?"
Regarding today's performance, Zhou Suhong confessed that her feeling now was as bad as (the same time in) 2006. The Chinese team did not have much strategy to deal with problems in the game, and losing the game makes the team feel embarrassed to face the audience.
Mandarin
灯火渐渐地缩小了,在预告石油的已经不多;石油又不是老牌,早熏得灯罩很昏暗。
燈火漸漸地縮小了,在預告石油的已經不多;石油又不是老牌,早燻得燈罩很昏暗。
dēng huǒ jiàn jiàn de suō xiǎo le , zài yù gào shí yóu de yǐ jīng bù duō ; shí yóu yòu bù shì lǎo pái , zǎo xūn de dēng zhào hěn hū nàn .
X
Mandarin
那陆畹香的一笑一颦,竞和那章秋谷的一顾一盼互相关合,差不多就和无线电机一般,不期而然的两边相应。
那陸畹香的一笑一顰,競和那章秋谷的一顧一盼互相關合,差不多就和無線電機一般,不期而然的兩邊相應。
nà lù wǎn xiāng de yī xiào yī pín , jìng hé nà zhāng qiū gǔ de yī gù yī pàn hù xiàng guān hé , chā bù duō jiù hé wú xiàn diàn jī yī bān , bù qī ér rán de liǎng biān xiàng yìng .