Learn Arabic (Modern Standard): ما قياس هذا الحذاء الوردي؟ - What is the measurement of this pink shoe?

In Arabic, ما is used when asking "what" before a noun or in a nominal sentence (a sentence without a verb). Since قياس (measurement or size) is a noun and there is no verb in this sentence, we use ما. You would use ماذا if you were asking "what" before a verb.

Why does قياس not have ال (the) at the beginning?

The phrase قياس هذا forms an idafa (a possessive construction meaning "the measurement of this"). In an idafa, the first word never takes ال, even though it is translated into English with "the".

Why does الحذاء (shoe) have ال (the) attached to it right after هذا (this)?

When you want to say "this shoe" as a single descriptive phrase, the noun following the demonstrative هذا (this) must have ال. If you left the definite article off and said هذا حذاء, it would turn into a complete sentence meaning "This is a shoe".

Why does the adjective الوردي (pink) also have ال?

Adjectives in Arabic must match the noun they describe in definiteness. Because الحذاء is definite (it has ال), the adjective الوردي that describes it must also take ال to match.