Answer:
not a right triangle
Step-by-step explanation:
We can use the Pythagorean theorem to see if it is a right triangle
a^2 + b^2 = c^2
15^2 + 12^2 = 21^2
225 + 144 = 441
369 = 441
This is not true so it is not a right triangle
Answer: 3:4
Step-by-step explanation:
If you divide both 30 and 40 by 10 you get 3 and 4
Since it says blue:green the answer is 3:4
Options 3, 5 would be the answer