Answer:
The base is decreasing at 2 cm/min.
Step-by-step explanation:
The area (A) of a triangle is given by:
[tex] A = \frac{1}{2}bh [/tex] (1)
Where:
b: is the base
h: is the altitude = 10 cm
If we take the derivative of equation (1) as a function of time we have:
[tex] \frac{dA}{dt} = \frac{1}{2}(\frac{db}{dt}h + \frac{dh}{dt}b) [/tex]
We can find the base by solving equation (1) for b:
[tex] b = \frac{2A}{h} = \frac{2*120 cm^{2}}{10 cm} = 24 cm [/tex]
Now, having that dh/dt = 1 cm/min, dA/dt = 2 cm²/min we can find db/dt:
[tex] 2 cm^{2}/min = \frac{1}{2}(\frac{db}{dt}*10 cm + 1 cm/min*24 cm) [/tex]
[tex]\frac{db}{dt} = \frac{2*2 cm^{2}/min - 1 cm/min*24 cm}{10 cm} = -2 cm/min[/tex]
Therefore, the base is decreasing at 2 cm/min.
I hope it helps you!
