1 ft equals 12 in. So 2ft equals 24 in. 24 in plus 5 in equals 29 in, and 29 in plus 9 in equals 38 in. 38/12 equals 3 ft 2 in.
Answer:
are a, b, and c the options or are they different questions?
Answer with explanation:
Let us assume that the 2 functions are:
1) f(x)
2) g(x)
Now by definition of concave function we have the first derivative of the function should be strictly decreasing thus for the above 2 function we conclude that

Now the sum of the 2 functions is shown below

Diffrentiating both sides with respect to 'x' we get

Since each term in the right of the above equation is negative thus we conclude that their sum is also negative thus

Thus the sum of the 2 functions is also a concave function.
Part 2)
The product of the 2 functions is shown below

Diffrentiating both sides with respect to 'x' we get

Now we can see the sign of the terms on the right hand side depend on the signs of the function's themselves hence we remain inconclusive about the sign of the product as a whole. Thus the product can be concave or convex.
Answer:
351.68 cm^2
Step-by-step explanation:
We need to find the area of the frame itself. the radius of the inner circle is 12, but the frame has a radius of 4. You add 12 and 4 and you get 16. The formula for area of a circle is A=πr^2. So A= 3.14 x16^2. Then you have A= 3.14x 256 and you get 803.84. But we only want the area of the frame, so you have to get the area of the inner circle and subtract. You get A= 3.14 x 12^2. 3.14x144 is 452.16. 803.84-452.16 is 351.68. Hope this helped. :)