Okay first, use the sin rule (

so

sin^-1 this and you get 47.928....this is angle ADB
and as it is on a straight line, 180 - this angle gets ADC
180 - 47.928.... = 132.07
Answer:
$2400
Step-by-step explanation:
60 tonnes = $1800
80 tonnes = $?
= 1800 × 80/60
= $2400
P = 77.
side (S1, S2) = 2(B) - 4.
P = S1 + S2 + B.
77 = (2B - 4) + (2B - 4) + B.
77 = 2B - 4 +2B - 4 + B.
77 = 5B - 8.
77 + 8 = 5B.
85 = 5B
B = 85/5
B=17 ft