Here's why:
* Spelling: The vowel "i" is followed by a consonant ("d") and a silent "e" at the end of the word. This is a common pattern for long vowel sounds in English.
* Sound: The "i" in "slide" makes the same sound as the "i" in "bike" or "time," which are both long vowel sounds.
Let me know if you have any other vowel sounds you'd like to explore!