This question stumped me for a very long time, since it had multiple parts that weren’t all trigonometry. For example, I was not sure if I had to use the distance over time triangle from physics, or if I should use unit analysis from the measurement unit. I tried many different things, and I finally found out how to solve the problem!
At first I used sine to figure out the length of the hypotenuse, but later on as I thought about it, I realized it would not make sense. The biker is going along a highway, it’s impossible to travel along the hypotenuse side! So I changed the equations:
I multiplied 20s by 3 into 60s, which is 1 minute. Then I multiplied it by 60 to convert it into 1 hour. You must do the same to the top numbers, so I got an answer of:
So the average speed the biker travelled at is 77km/hr!