The cost of my me knife is $5.52
3.5 - 3.2 = 3.8 - 3.5 = 4.1 - 3.8 = 0.3 (common difference)
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