The phrase "approximate to" is commonly used to convey an estimation or an approach to a certain value or quantity. However, there are several other synonyms that can be used to express a similar meaning. Words such as "near", "close to", "almost", "just about", "nearly" and "roughly" are some of the examples. Each of these words can be used interchangeably with "approximate to" to express an approximation or a close proximity to a value or quantity. It's important to keep in mind the nuances of each synonym, as they may differ slightly in the context of the sentence.