Your answer is b because something
(0,0) is the 4th vertex you are looking for
The irrigation arm is 300 ft. 300 ft is just the radius. The diameter is 600, because to get the diameter you must multiply the radius by two. So 600 is the land the irrigation arm covers.
(10,50)(30,86)
slope = (86 - 50) / (30 - 10) = 36/20 = 1.8
y = mx + b
slope(m) = 1.8
(10,50)...x = 10 and y = 50
now sub and find b, the y int
50 = 1.8(10) + b
50 = 18 + b
50 - 18 = b
32 = b
ur equation is : y = 1.8x + 32
when fahrenheit is 20....y = 20
20 = 1.8x + 32
20 - 32 = 1.8x
-12 = 1.8x
-12/1.8 = x
-6.67 = x....celsius would be -6.67
1/6 + 5\6
2/6 + 4\6
3/6 + 3/6