Answer:
(1)  D.Angle C is congruent to to Angle F. (2) C. SSS. (3) C. cannot be congruent to.
Step-by-step explanation:
1)
From the given figure it is noticed that


According to SAS postulate,  if two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then both triangles are congruent.
The included angles of congruent sides are angle C and angle G.
So, condition "Angle C is congruent to to Angle F"  will prove that the ∆ABC and ∆EFG are congruent by the SAS criterion.
2)
If 
According to SSS postulate,  if all three sides in one triangle are congruent to the corresponding sides in the other.
Since two corresponding sides are congruent but third sides of triangles are not congruent, therefore SSS criterion for congruence is violated. 
3)
Since two corresponding sides are congruent but third sides of triangles are not congruent, therefore the included angle of congruent sides are different.

Therefore angle C and angle F cannot be congruent to each other.
 
        
             
        
        
        
Answer:
A
Step-by-step explanation:
the a and b i put on my triangles should be E and E'. sorry
 
        
             
        
        
        
Answer:
The GCF is going to be 30
Step-by-step explanation:
This Is how I find the GCF of 2 numbers. I find the prime factorization first, then I find the common factors and multiply them. Here
The prime factorization of 21, 2 × 3 × 3 × 5= 90
The prime factorization of 28, 2 × 3 × 5 × 7 = 210
The common factors are, 2, 3, and 5. We multiply those to get the GCF.
2 × 3 × 5 = 30
 
        
             
        
        
        
The answer is 168 seconds.