Answer:
a = ±10/9
Step-by-step explanation:

 
        
                    
             
        
        
        
Answer:
∠a = 45°
Step-by-step explanation:
We are told that △abc and △xyz are congruent.
Thus;
∠a = ∠x
∠b = ∠y
∠c = ∠z
We are given;
∠y = 90°
Thus, ∠b = 90°
Now,we are told that ∠a is one half the size of ∠b.
Thus; ∠a = ½ × ∠b
∠a = ½ × 90
∠a = 45°
 
        
             
        
        
        
Answer:
by how much degrees should the heat be reduced in the last 5 minutes of banking
 
        
             
        
        
        
Answer:
22
Step-by-step explanation:
Pretend the 10 values in the first sentence are a,b,c,d,e,f,g,h,i,j
Pretend the addition 5 values is k,l,m,n,o
So the mean of all the 15 data is (a+b+c+d+e+f+g+h+i+j+k+l+m+n+o)/15=20
So the sum of all 15 data is  a+b+c+d+e+f+g+h+i+j+k+l+m+n+o=300                since 15(20)=300
Now let's look at the first 10:  We have their mean so we can write:
(a+b+c+d+e+f+g+h+i+j)/10=19
so a+b+c+d+e+f+g+h+i+j=190                               since 10(19)=190
So that means using our first sum equation and our equation sum equation we have 
190+k+l+m+n+o=300
       k+l+m+n+o=300-190
       k+l+m+n+o= 110
So the average of those 5 numbers mentioned in your problem is 110/5=22