If triangle ABC is equilateral, you know that each angle is 60 degrees because 180(the total of all angles in a triangle) divided by 3 is 60. 60 would equal 3x-12. 60=3x-12 then you cancel out the 12, 56=3x, and finally divide by 3... x=18.66! Hope this helps!
Given:
Three numbers in an AP, all positive.
Sum is 21.
Sum of squares is 155.
Common difference is positive.
We do not know what x and y stand for. Will just solve for the three numbers in the AP.
Let m=middle number, then since sum=21, m=21/3=7
Let d=common difference.
Sum of squares
(7-d)^2+7^2+(7+d)^2=155
Expand left-hand side
3*7^2-2d^2=155
d^2=(155-147)/2=4
d=+2 or -2
=+2 (common difference is positive)
Therefore the three numbers of the AP are
{7-2,7,7+2}, or
{5,7,9}
The total number of mattresses that are sold in a year = 1,330
Percentage of King size mattresses sold = 30% = 30/100 = 0.3
Next, we have to calculate the actual number sold by using the formula given below:
Number of king size mattresses sold = Total mattresses sold in a year * percentage of king size mattresses sold
Number of King Size mattresses sold = 1,330*0.3 = 399
Number of king size mattresses sold = 399
Answer:
this is geometry?
Step-by-step explanation: