Answer:
We can think about what happens to the ratios as the angle gets closer and closer to 90°.
The opposite (vertical) side gets closer and closer to 1, which is also the length of the triangle's hypotenuse on the unit circle. So, the sine ratio becomes:
sin(θ) = opposite / hypotenuse
= 1 / 1
= 1
We can also think about this as a "flat triangle" where:
- opposite = 1
- adjacent = 0
- hypotenuse = 1
So:
cos(θ) = adjacent / hypotenuse
= 0 / 1
= 0
tan(θ) = opposite / adjacent
= 1 / 0
=> undefined
