First get the tangent vectors by differentiating r1 and r2

Evaluate at t=0

Use identity for angle between 2 vectors:

Evaluate dot product and unit vectors:

Sub into identity and solve for theta:

Answer:
Angle of intersection is about 79 degrees.
Simple interest formula
Interest = Pit = $50
P=principal (initial investment)
i=annual interest rate = 0.04
t=time in years = 6 months = 0.5 years
Substitute values,
$50 = P*0.04*0.5
Solve for P
P=$50/(0.04*0.5)=$2500
Answer:
Step-by-step explanation:
Two faces are 6” by 9”. Two faces are 6” by 2”. Two faces are 9” by 2”.
Surface are = 2*6*9 + 2*6*2 + 2*9*2 = 108 + 24 + 36 = 168 square inches
Answer in screen shot below
Angle TQS is equal to 74 degrees