Oh, dude, it's "radios'." Like, you just add an apostrophe after the "s" when you want to show that multiple radios own something. So, if you're talking about the antennas on a bunch of radios, you'd say, "The radios' antennas are all tangled up." Easy peasy.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural of rose is roses. The plural possessive is roses'.
The plural possessive is governesses'.
Possessive for sofa is sofa's. Plural for sofa is sofas. Plural possessive is sofas'.
The plural is queens. The plural possessive is queens'.
The plural form of the noun radio is radios.The plural possessive form is radios'.Example: The radios' selection had several on sale.
The plural form of the noun radio is radios.The plural possessive form is radios'.Example: The radios' selection had several on sale.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is lads. The plural possessive is lads'.
The plural is relatives. The plural possessive is relatives'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is echoes. The plural possessive is echoes'.
The plural form is inches. The plural possessive is inches'.
Studies' is the plural possessive of study.
The plural possessive is pals'.