Question

Please help!!!!
full answers please!!

Answer 1

We must use the trigonometric function.

`(a)\\\sin(\angle BAC)=(ground)/(plank)\\\\\sin49^o=(3)/(|AC|)\\\\\sin49^o\approx0.7547\\\\(3)/(|AC|)=0.7547\\\\0.7547|AC|=3\ \ \ |:0.7547\\\\|AC|\approx3.9750\approx4\ ft.`
We can use the Pythagorean theorem.

`(b)\\|BC|^2+3^2=4^2\\\\|BC|^2+9=16\ \ \ |-9\\\\|BC|^2=7\to|BC|=\sqrt7\\\\|BC|\approx2.6458\\\\|BC|\approx3\ ft.`