Question

(10TH GRADE GEOMETRY PLSSS HELP ) What is the value of s to the nearest whole number?

10

12

13

14

Answer 1

D. 14

Explanation:

Edge 2021

Answer 2

Answer with explanation:

We will use Cosine law to find value of Side, RT whose length =s.

Cosine Law in Mathematical terms, that is , if a, b and c are sides of triangle

`b^2=c^2 +a^2-2 a c \cos B\\\\ \text{ In} \Delta RST\\\\s^2=9^2+8^2-2* 9 * 8 * \cos111^(\circ) \\\\s^2=81 +64 -144 * (-\cos 69^(\circ))\\\\\cos111^(\circ)=cos (180-69^(\circ))\\\\=-\cos 69^(\circ)\\\\s^2=81 +64 -144 *(- 0.358)\\\\s^2=145+51.55\\\\s^2=196.552\\\\s=14.0197`

→Cosine is negative in second quadrant, so value of cosine 111 is negative.

⇒Rt=s=14.0

⇒Option D : 14