#1
Apply pythagorean theorem
So
Diagonal
- √L²+B²
- √12²+9²
- √144+81
- √225
- 15ft
#2
Again apply
- H²=P²+B²
- H²=3²+9²
- H²=9+81
- H²=90
- H=√90ft
- H=9.5ft
To calculate the midpoint,here's the formula : ((x1+x2)/2 , (y1+y2)/2)
thus, we have:
((10+(-4))/2 , (6+8)/2)
=(6/2 , 14/2)
=(3,7)
The coordinate for the midpoint is (3,7)
hope it helps!
Answer:
x = 20
Step-by-step explanation:
You can use Pythagorean theorem which is 
a = 12
b = 16
and c would be x.
12^2 + 16^2 = c^2
144 + 256 = c^2
400 = c^2
square root
c = 20 or x = 20