Find ing the common denominator would make it 10.
for 1/2 to get to 10 you have to multiply by 5
1/2x5= 5/10
then you have to convert 2/5 to get the denominator to be 10
so you multiply 2/5 by 2
2/5x2= 4/10
5/10 is greater than 4/10
The triangles are similar, they aren't congruent (identical) though as we don't know if they share a common side
The mean book rating will decrease
Add all the numbers together:
5 + 5 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 9 + 9 + 10 + 10 + 10 + 10 + 10= 136
divide the total with the total amount of numbers
136/17 = 8
Now add all the numbers again WITH the one
5 + 5 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 9 + 9 + 10 + 10 + 10 + 10 + 10 + 1= 137
Divide the total amount with the amount of numbers there are
137/18 = 7.61
7.61 < 8
The mean book rating will decrease by 0.39
hope this helps