Number + 角 + Noun
角 (jiǎo) is a measure word and noun used to refer to corners, angles, or horn-like shapes. It appears in compound words to describe structures or shapes with prominent corners or points. For example, 五角大楼 (the Pentagon) literally means 'five-corner building.'
这个房间有四个角,每个角都放了一盆植物。
Zhège fángjiān yǒu sì gè jiǎo, měi gè jiǎo dōu fàng le yī pén zhíwù.
This room has four corners, and a potted plant is placed in each corner.
三角形的三个角加起来等于一百八十度。
Sānjiǎoxíng de sān gè jiǎo jiā qǐlái děngyú yībǎi bāshí dù.
The three angles of a triangle add up to one hundred and eighty degrees.
他不小心撞到了桌子角上,疼了好半天。
Tā bù xiǎoxīn zhuàng dào le zhuōzi jiǎo shàng, téng le hǎo bàntiān.
He accidentally bumped into the corner of the table and was in pain for quite a while.