Answer:
83.9°
Explanation:
Pythagorean theorem, the well-known geometric theorem that the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle)—or, in familiar algebraic notation, a2 + b2 = c2.
a= 13 cm
a2= 169cm
b= 4cm
b2=16 cm
a2+b2= 185cm (c2)
c=13.6cm
after wards use the law of cosines and c= 83.9°