2 Answers

CNeo · Answer 1 · 2020-08-05T09:08:40+0000

Answer:

14

Explanation:

Using the law of cosines on ΔRST, then

s² = 9² + 8² - (2 × 9 × 8 × cos111° )

= 81 + 64 - ( 144 × cos111° )

= 145 - (- 51.6)

= 145 + 51 . 6 = 196.6 ( take the square root of both sides )

s =
√(196.6) ≈ 14

Zini · Answer 2 · 2020-08-07T08:51:08+0000

Hello!

The answer is: 14

Using the law of cosines and the given information, we can find the value of s.

Law of cosines is:

a^(2)=b^(2)+c^(2)-2abcos(A)

Where,

$a=s\\b=9\\c=8\\A=111(degrees)$

By substituting we have:

$s=\sqrt{9^(2)+8^(2)-2*9*8*cos(111)}\\\\s=√(81+64-(144)*(-0.35))=√(145+50.4)=√(195.4)=13.98=14$

So, the correct answer is:

s=14

Have a nice day!