I think the answer is 3 route 5
First find a perfect square that goes into 45 in this case 9
Then as it's 9x5 simplify the nine to 3
Hope this helps
The third choice is correct and can be found by plugging the values into Point-Slope Form.
Use Pythagoras’ theorem:
a^2+b^2=c^2
But we rearrange this formula to make it
c^2-a^2=b^2
So 25^2-15^2=b^2
625-225= b^2 = 400
You now need to find the square root of 400 to find the square root of b
sqrt of 400 is 20
So 20 is the missing length in this triangle