ACT has never provided math formulas on their tests. However, there is one noticeable formula that has been introduced into the last two tests, April & June 2018.
The area for any triangle is given by one-half the product of the lengths of two sides times the sine of their included angle. This formula is necessary when finding the area of a triangle which does not contain a right angle.
Area= 1/2 bc sin A
Area= 1/2 ab sin C
Area= 1/2 ac sin B