CD = x
BC = y
AB = 85
BD = BC+CD = y+x
tan(angle) = opposite/adjacent
tan(28) = BC/AB
tan(28) = y/85
85*tan(28) = y
y = 85*tan(28)
y = 45.1953016912257
tan(angle) = opposite/adjacent
tan(31) = BD/AB
tan(31) = (y+x)/85
tan(31) = (45.1953016912257+x)/85
85*tan(31) = 45.1953016912257+x
51.0731526173427 = 45.1953016912257+x
51.0731526173427-45.1953016912257 = 45.1953016912257+x-45.1953016912257
5.877850926117 = x
x = 5.877850926117
So CD is roughly 5.877850926117 meters
25 feet = 25 x 12 = 300 inches
First light is at 16 inches.
300 - 16 = 284 inches
Find the rest of the bulbs:
284 ÷ 4 = 71
Total number of lights = 71 + 1 = 72
Answer 72 lights
Nothing times itself will equal 29, but in decimal form only is 5.38
The answer is 31/3 or 10⅓