Area=pi times radius^2 so
if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative
radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4
The set of two-digit primes is {11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}
Of that list, the following primes are mirror images of each other
13 and 31
17 and 71
37 and 73
79 and 97
Note: we ignore 11 since 11 flips to 11 which is not distinct from its original
If you're looking for the largest prime of this form, then its 97
If you're looking for the largest gap, then subtract each pair
31-13 = 18
71-17 = 54
73-37 = 36
97-79 = 18
We see that 71 and 17 have the largest gap
3x + 4y = - 8
The equation of a line in standard form is Ax + By = C
where A is a positive integer and B, C are integers
Express the line in ' slope- intercept form '
y = mx + c → (m is the slope and c is the y-intercept)
here m = - 
and c = - 2
hence y = - x - 2 → equation in slope- intercept form
multiply all terms by 4
4y = - 3x - 8
add 3x to both sides
3x + 4y = - 8 → in standard form
Answer: 40
Align in this pattern:
Bigger box : 24 : 15 : 10
smaller box: 6 : 3 : 5
counts: 4: 5 : 2
( multiply 4*5*2 = 40)
