You can use the cosine rule for this - you might have to change some of the letters around for it to make sense though. Hope this helps!
Answer:
19
Step-by-step explanation:
9+10 is 19.
Answer:

Step-by-step explanation:
We know that since angles in a triangle add up to 180º, the remaining angle must be 45º.
So the side with length
must be equal to the side with length
. That is:

Now, by Pythagoras:

Answer:
y=-7
x=3
Step-by-step explanation:
I just used a calculator. Hope this helps. :)
It is 12 sense the perimeter is the outside of the square you have to add the 2 numbers by themselves because they are the same measurement and 5+5=10 1+1=2 10+2=12