Answer:
7) X = a^2 + b^2 = c^2
 X = (4^2) + (8^2) = c^2
 X = 80^2 = c^2
 X = √80 = 8.944
 X = 8.9 = c^2
8) X = a^2 + b^2 = c^2
 X = (6^2) + (3^2) = c^2
 X = 45^2 = c^2
 X = √45 = 6.708
 X = 6.7 = c^2
9) X = a^2 + b^2 = c^2
 X = (7^2) + (10^2) = c^2
 X = 149^2 = c^2
 X = √149 = 12.206
 X = 12.2 = c^2
10) X = a^2 + b^2 = c^2
 X = (3^2) + (7^2) = c^2
 X = 58^2 = c^2
 X = √58 = 7.615
 X = 7.6 = c^2
11) X = a^2 + b^2 = c^2
 X = (7^2) + (2^2) = c^2
 X = 53^2 = c^2
 X = √53 = 7.280
 X = 7.3 = c^2
12) X = a^2 + b^2 = c^2
 X = (2^2) + (6^2) = c^2
 X = 40^2 = c^2
 X = √40 = 6.324
 X = 6.3 = c^2
Step-by-step explanation:
X = a^2 + b^2 = c^2
X and c^2 = missing side
a^2 and b^2 = the two legs of the triangle (the mesurments of the sides that are given)
c^2 = hipatanouse 
The formula is called Pythagromtherom (a^2 + b^2 = c^2)