Answer:
First one is not possible
Second one is possible, and would be an isocèles triangle
Third one is possible, would be scalene
Last one is not possible
Comment any further questions :)
Step-by-step explanation:
No it is not because 15 out of 30 is half but 12 out of 20 is more than half
EDIT: MY ANSWER ASSUMED CONSTANT ACCELERATION - CHANGING IT NOW
