ElectricPavlov

g = 2 r

r

2r-42  = 1/2 r

3/2 r = 42

r = 28       g = 2r = 56         56 + 28 = number of pencils originally       56 + 28 - 42 = pencils after he lost 42

Answered in your post yesterday.....did you even look at it?   ( the ONLY difference being it is +4  instead of +3 at the end in this Q !!)

https://web2.0calc.com/questions/please-help_97798

total are of circle =  pi r^2  =  64 pi

The fraction of 2pi radians (a whole circle) that is 5pi/4    is     5 pi/4   /   2 pi =  5/8

5 / 8      x    64 pi = ........ ft²

From -2     to 2   is + 4 units of change      f(x)   changes from  25 to 9   a change of -16

avg rate of change/unit    =    -16/4  =  -4 /unit

Use law of cosines

c^2 = a^2 + b^2 - 2ab cos 63^o         c is the distance you are looking for    a = 80   b=140      solve for 'c'

T = Tahoe days          cost   350 T

9-T = S                      cost   475 (9-T)      summed  = 3650

350 T        +      475 (9-T)        = 3650             solve for T (Tahoe days)     then # San Fran days  =   9 -T

Here is a possibility

Stack A has     6 red 24 black

Stack B has     20 red 2 black    =  22 cards in stack B

2c +4a =38

14c +12a = 138      multipy top equation by  -3

-6c -12a = -114      add to the second equation

8c           = 24         solve fo c....

58 of them so far this year        58/72 x 100% = 80.56 %

Take 1/2 of the 'x' coefficient     11  * 1/2 = 5.5     now square it and add it to both sides of the equation (the blanks in your question)

5.5²  = 30.25