58. Determine the area of a triangle if its three sides are given:
1) $a=13 ; b=14 ; c=15 ; 2) a=5 ; b=12 ; c=13$.

## Task by Hypsicles.
58. Answer. 84; 30 (the second triangle is right-angled).

Hypsicles of Alexandria (150 BC), a geometer to whom the XIV book of Euclid's "Elements" (on the properties of regular polyhedra) is attributed. Problem 59 is found in the work "Anaphorikos."