Answer:a.c,d
Step-by-step explanation:
 
        
             
        
        
        
Answer:
   = 3052.08 cm^3
Step-by-step explanation:
Volume of a sphere is given by 
V = 4/3 pi r^3
We know the diameter is 18
d = 2r
18 = 2r
Divide each side by 2
18/2 =2r/2
9 =r
V = 4/3 pi 9^3
V = 4/3 pi (729)
V = 972 pi
Approximating pi by 3.14
V =972 (3.14)
   = 3052.08 cm^3
 
        
             
        
        
        
Let Sam be (S+8) years while his sister is S years.
S(S+8) = 105
S^2+8S-105 = 0
(S+15)(S-7) = 0
Sam’s sister is 7 years and Sam is 15 years old.
        
             
        
        
        
We notice that the upper trapezoid is symmetric to the lower one & the line of symmetry should be a horizontal line (mirror line) where any point of the upper vertices should be at equal distance (perpendicular) with the related vertices of the lower one from this horizontal line:
Note that QQ" =4 units, Hence the line of symmetry is the perpendicular to QQ' at 2 units