Answer:
180°
Step-by-step explanation:
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
17-8 because they both have just 1 added to them
Sin= opp/hyp
sin = 8sqrt(3)/16
= 2sqrt(3)/4
= sqrt(3)/2
Answer: 2nd choice