we are given
The water level in Ricky lake changes at an average of -7/48 inch for 1 year
It means that
In 1 year , the water level changes at 
and we have to find the water level change after 5 years
so, we can multiply both sides by 5
In 5*1 year , the water level changes at 
In 5 years , the water level changes at 
Hence,
the water level change after 5 years is
........Answer
The law of cosines states that:
c^2=a^2+b^2-2abcosC
You already have all the values for the variables with the exception of x so:
x^2=25+100-100cos60
x=√(125-100cos60)
x=√75
x≈8.66 to nearest one-hundredth...
Answer:
306mm²
Step-by-step explanation:
the height h = 86/2 -34 = 43-34=9mm
the area = 34×9= 306mm²