When "り" combines
with the youon "ゃ",
it is pronounced as
"りゃ" (rya).

When "り" combines
with the youon "ゅ",
it is pronounced as
"りゅ" (ryu).

When "り" combines
with the youon "ょ",
it is pronounced as
"りょ" (ryo).

How is it?
Simple once you know the rule, right?