21. Broooooo, This is baby stuff!
 
        
                    
             
        
        
        
The <em><u>correct answer</u></em> is:
AAS
Explanation:
AAS stands for "angle-angle-side."  This states that if two angles and a non-included side of one triangle are congruent to the corresponding two angles and non-included side of another triangle, then the triangles are congruent. 
In these triangles, we have ∠CAB ≅ ∠CDB given to us to begin with.  Throughout the proof, we find that ∠ABC ≅ ∠DCB.  We also have that CB is congruent to itself.  This is two angles and a side not included, so this is AAS.
 
        
                    
             
        
        
        
The expression for 7(2+9) IS A(B+C) which is distributive property of addition over multiplication.
Only two arithmetic procedures are subject to the commutative property: Multiplication and Addition
  A + B = B + A Which is Commutative property of addition
 A.B = B.A, which is a commutative property of multiplication.
Distributive property is A(B+C) =AB+AC
 The operation on numbers that are available in brackets can be distributed for each number outside the bracket, according to the distributive property. It is one of the mathematical properties that is used the most. Commutative and associative qualities are the other two important features.
from the given data 7(2+9) =7*2+7*9
                                                 =14+63
                                                 =77
 Now, we can clear that 7(2+9) =7(9+2) 
Hence, the expression for commutative property of addition is A(B+C) = AB+AC.
To learn more about commutative property, visit 
brainly.com/question/28387735
#SPJ1
 
        
             
        
        
        
Answer:
250 ml= 1 pancake
1000 ml=4 pancakes
Step-by-step explanation:
