When you go from nine to ninety you do not drop the 'e'. And therefore it is ninety and not ninty. For example, if you write, 'I am ninetynine percent times right', your spellings are actually hundred percent right.
Ninety-degree temperatures are heating up parts of North Carolina. While all of the state's residents are feeling the effects of the warm weather, the Department of Health and Human services said men are particularly vulnerable to heat.