<span>Just find the volume of each cube separately and add together the results. First cube has side length 5h^2. What is the formula for the volume of a cube? Second cube has side length 3k. Whats its volume?</span>
Answer:
Step-by-step explanation:
Given
Fireplace is in the form of semi-ellipse with height of 3 ft from center
Length of base=8 ft
if the arch is in the form of ellipse then it can be considered as horizontal ellipse with 2 a and 2 b be length of major and minor axis
2 a =8
a=4 ft
If contractor cover the whole base
then total length of string=2a =8 ft
(b)String should be nailed at focus
focus of ellipse is a e
where e=eccentricity


Focus 
Thus string should be nailed at 2.64 m from center
Matrix :
1 4 4
5 2 2
1 5 5
=> Determinant =
1 * (2*5 - 2*5) - 4 * (5*5 - 1*2) + 4 * ( 5*5 - 2*1)
= 1*(10 - 10) - 4*(25 - 2) + 4*(25 -2) = 1*0 + 4* 23 + 4*(25 - 2) = 0 - 4*23 + 4*23 = 0
Answer: 0