Answer: 29.8ft
Explanation:
suppose that the angles are measured from an x-axis.
we know that:
Lila and Avery are 20 feet apart.
Mark and Avery are 30 feet apart.
If we locate the position of Lila in the (0, 0)
and we use the relation:
x = r*cos(θ) and y = r*cos(θ)
Then the position of Avery is:
P = (20ft*cos(90°), 20ft*sin(90°)) = (0, 20ft)
and the position of mark will be:
P = (0 + 30ft*cos(200°), 20ft + 30ft*sin(300)) = (-28.2ft, 9.7ft)
And because Lila is at the origin, the distance between Mark and Lila is equal to the module of that vector,
Distance = √((28.2ft)^2 + (9.7ft)^2) = 29.8ft