In a parallelogram, two adjacent sides measure 10 cm and 12 cm. The shorter diagonal is 15 cm. Determine, to the nearest degree, the measures of all four angles
+130536 By the Law of Cosines, we have
15^2 = 10^2 + 12^2 - 2(10)(12) cos(x)
And solving this for x, we have
cos-1 [ ( 225 - 100 - 144) / -240 ] = x = about 85.46”.......and the angle opposite this one will be the same
The other two opposite angles will measure (180 - 85.46)° = about 94.54° each
