Question

Evaluate the value of x to 1 d.p Thank you

Answer 1

Answer:

value of x = 2.8

Step-by-step explanation:

By law of cosines,

${a}^{2} = {b}^{2} + {c}^{2} - 2 \times b \times c \times cos(100) \\ {x}^{2} = {13}^{2} + {10}^{2} - (2 \times 13 \times 10 \times cos100) \\ = 169 + 100 - 260 \times 0.862 \\ = 269 - 260 \times 0.862 \\ = 7.758 \\x = \sqrt{7.758 } \\ = 2.785 \\ = approx \: 2.8$