Leila purchased 21.5 centimeters of wire for $17.20.
1 answer:
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Answer:
-0.69 feet per second
Step-by-step explanation:
We have dx/dt = 2 ft/sec, and we want to determine dy/dt.
x and y are related by the Pythagorean Theorem.
x²+y²=16²
Differentiate both sides of this equation with respect to t to get
Divide both sides by 2y
When x = 5 ft, we have
x²+y²=16²
5²+y²=256
y²=256-25=231
therefore
y=
=-0.69
The top of the ladder is sliding down (because of the negative sign in the result) at a rate of -0.69 feet per second.
Answer:
The time it takes to boil 2.2 litres of water is approximately 141 seconds
Step-by-step explanation:
The given parameters are;
The relationship of the variables, T and A is a proportional, therefore, we have;
T ∝ A, or T/A = k = Constant of proportionality
The time it takes to boil 2.8 liters of water = 180 seconds
∴ When A = 2.8 litres, T = 180 seconds, from which we have;
k = T/A = 180 s/(2.8 L) = 450/7 s/L
k = 450/7 s/L
When A = 2.2 litres, we have;
T/A = k
∴ T = k × A
Plugging in the value for both 'k', and 'A' when A = 2.2 litres, gives;
T = k × A = 450/7 s/L × 2.2 L = 990/7 s = 141. s
The time it takes to boil 2.2 litres of water, given a direct proportionality relation is, T = 141. seconds ≈ 141 seconds given to the nearest second.
Set up a proportion
= 
Use cross-multiplication
= 
Simplify
x = 19.2
Use cross-multiplication
Simplify
x = 19.2