This the concept of circumference of circle. The arc length will be given by:
C=theta/360*pi*diameter
theta=62
diameter=d
thus the arc length will be:
C=62/360*π*d
C=0.54d
9)

11)
(a²b)³ = a²⁽³⁾b¹⁽³⁾ = a⁶b³
12)
The exponent tells you how many places to move the decimal. The positive/negative sign tells you which direction to move the decimal (negative is left, positive is right).
8.4 x 10⁻⁵ <em>move the decimal 5 places to the left</em> = 0.000084