Perimeter of Triangle2S=26+28+30=84⇒S=42cmArea s(s−a)(s−b)(s−c)​ (Heron's formula)Area =42(42−26)(42−28)(42−30)​=42×16×14×12​Area=336cm2Area of parallelogram = Area of triangle⇒ h×28=336⇒h=12cmHeight of parallelogram =12cm