Answer:
The angle the running and the skateboarding path ≈ 51.2°(to the nearest tenth)
Explanation:
The course takes the shape of a triangle. That means it has three sides.
One side of the triangle(biking path) = 51 meters , another side(skateboarding) = 64 meters . The angle opposite the skateboarding path = 78°. The angle opposite the biking path is what we are ask to find.
Using sine rue we can find the angle opposite the biking path which is the angle between the running and skateboarding path. Note we used the sine rule because 2 sides are given and a non included angle
a/sin A = b/sin B = c/sin C
51/sin A = 64/sin 78°
cross multiply
51 sin 78° = 64 sin A
sin A = 51 sin 78°/64
sin A = (51 × 0.97814760073) /64
sin A = 49.8855276374/64
sin A = 0.77946136933
A = sin⁻¹ 0.77946136933
A = 51.2112853091
A ≈ 51.2°(to the nearest tenth)