Circumference: 2πr C=18 so r= 18/2π= 9π
Arc length = rθ 6=(9π)θ θ=6/9π
Convert to degrees by multiplying by 180/π
6/9π x 180/π = 120 degrees
Let's find the derivative of that hyperbola in order to find a slope formula to help us with this equation. We already have an x and y value. The derivative is found this way:

so

. The derivative supplies us with the slope formula we need to write the equation. Sub in the x value of 3 to find what the slope is:

. So in our slope-intercept equation, x = 3, y = 1, and m = -1/3. Use these values to solve for b.

so b = 2. The equation, then, for the line tangent to that hyperbola at that given point is
Since we are calculating the amount that he got correct, we must divide the numerator by the denominator or make the denominator equal 100. I will do it the second way as it is easier in this case.
25*4 = 100
21*4 = 84
84/100 = 0.84
As a decimal, Andrew got 0.84 of his test correct. Hope this helps!
An area of rectangle: a · b
a = 0.4 km
b = 0.07 km
a · b = 0.4 km · 0.07 km = 0.028 km²