Y = 0.8
4x + 8y = 40
4x + 8*(0.8) = 40
4x + 6.4 = 40
4x = 40 - 6.4
4x = 33.6
x = 8.4
The answer is D. I graphed it on Desmos Graphing Calculator and I've linked the screenshot.
Hope this helps :)
The length of the arc intercepted by a central angle is the ratio of the angle to 360 degrees times the circumference. From the given values above,
S = (30° / 360°) x 2 x π x (6 ft)
S = π
The angle intercepted an arc which measures π feet. The answer is letter A.