Question

Evaluate the value of x to 1 d.p


Thank you

Answer 1

value of x = 2.8

Explanation:

By law of cosines,

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