Answer:
The circumference of a circle is C = 2πr^2 (2nd power) Radius (r) is the distance from the center of the circle to the outside of it. To find radius divide the diameter (d) by 2. The diameter (d) of a circle is the radius (r) multiplied by 2. To find the diameter (d) you need to do C ÷ π.
For example):
Finding diameter - 76/3.14 = 24.19 (d)
Finding radius - 24.19/2 = 12.095 (r)

negative 24 minus 16x (-1) divided by 6^2 divided by 9
ANSWER
four divided by 81 and than X minus 24
Mars year is 1.88 of your Earth years.
So if you are 13,
1.88 x 13=24.44, or 24 years old, I think.