Given series is 2.4,-4.8,9.6,-19.2
To find whether it has common difference or common ratio let us find few differences and few ratios of consecutive terms.
Common difference of first 2 terms = 2nd term - first term = -4.8-2.4 = -7.2
Common difference of 2nd and 3rd terms = 3rd term - 2nd term = 9.6-(-4.8) = 14.4
Since those common differences are not equal the given series does not have common difference at all.
To check if it has common ratio or not let us find few ratios of consecutive terms.
Common ratio of first 2 terms =
= 
Common ratio of 2nd and 3rd terms = 
So, the given series has common ratio as -2.0
The sum of the angles in a triangle is 180, so the equation will be :
2k+k+45= 180
add similar variables
3k+45=180
3k=135 (divide each side by 3)
k= 45
So 2k equals= 90
k=25
This is right angle triangle for your info!
Volume = pi*r^2
so 58^2*pi= 3364pi = approx 10,562.96 in^2
May has 31 days
31 x 24 = 744 hours in may
744 x 40 = 29760 watt hours
29760 watt hours = 29.76 kwh
29.76 x 75 = 2232 cents
2232 cents = $22.32