The angle between two vectors is:
CosФ = u - v / Magnitude(u) x magnitude(v)
Magnitude of u = SQRT(7^2 + -2^2) = SQRT(49 +4) = SQRT(53)
Magnitude of v = SQRT(-1^2 +2^2) = SQRT(1 +4) = SQRT(5)
u x v = (7 x -1) + (-2 x 2) = -7 + -4 = -11
cosФ = -11 / sqrt(53) x sqrt(5)
cosФ = -11sqrt265) / 265
Ф =cos^-1(-11sqrt265) / 265)
Ф=132.51 degrees.
Answer:

Step-by-step explanation:
Just Square the numbers like a normal equation.
4² = 16
9² = 81
This gives us 
or 0.198 as a decimal (approx)
Answer:
x=2
Step-by-step explanation:
The rectangle is 1-(-2) = 3 units in the real direction and 4i-(-3i) = 7 units in the imaginary direction. Its area is 3×7 = 21 square units.