Can someone help me with this trigonometry question

Explanation:

Apply the law of cosines to find angle C

c^2 = a^2 + b^2 - 2*a*b*cos(C)

19^2 = 11^2 + 17^2 - 2*11*17*cos(C)

361 = 121 + 289 - 374*cos(C)

361 = 410 - 374*cos(C)

361 - 410 = -374*cos(C)

-49  = -374*cos(C)

-374*cos(C) = -49

cos(C) = (-49)/(-374)

cos(C) = 0.131016042780749   which is approximate

C = arccos(0.131016042780749)

C = 82.4716905247836

C = 82 degrees

Notes:

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40