ElectricPavlov

Good work!     But the answer is in units of    mm²

For x   from end point to midpoint is  moving from 1   to 3  <---- a distance of 2    add 2 more to get to the other endpoint = 5

for y     from                                                             6 to -2    a move of -8  add another -8 to get to   -10

ABC is a right angle

 tan A = 8/5

A = arctan (8/5) = ........ ^o         (use calculator)

Big rectangle in middled    12 x 7    units²

Then FOUR triangles   4   *     ( 1/2 *  3 * 2)   units²

Add the reds together for total surface area   

y= -5/2cos (8x-pi)

Y = -5/2 cos( 8 (x-pi/8))    ?????    Not sure what you are asking.....

( 19 + 14 + 13 + 17) / 4 = AVERAGE

29^o 25'  = 29.4167 ^o

tan (29.4167) = opposite / adjacent =  height / 86

86 tan (29.4167) = height

You know there are 31 days in January

31 + x = 47

x = 16    of Feb

In the small triangle....h is to 4        In the larger triangle   3 is to  (2+4)