Answer:
210.6 cm
Step-by-step explanation:
Given that a piece of ribbon is cut into two shorter pieces in the ratio 2.8:1.25.
So that means length of the first smaller piece = 2.8x
and length of the second smaller piece = 1.25x
Then difference between their lengths = 2.8x-1.25x = 1.55x
Given that difference is equal to 80.6 centimeters then we get
1.55x=80.6
or x= 80.6/1.55
or x=52
then length of the original piece = 2.8x+1.25x
= 2.8*52+1.25*52
= 145.6+65
= 210.6 cm
Answer:
The correct options are 1, 3 and 4.
Step-by-step explanation:
We need to find the expressions whose simplified form is a rational number.
Rational number: If a number is defined in the form of p/q where p and q are integers and q≠0, then it is called a rational number.
For example: 0,2, 4.3 etc.
Irrational number: If a number can not defined in the form of p/q, where p and q are integers and q≠0, then it is called an irrational number.
First expression is

12 is a rational number.
Second expression is

is an irrational number.
Third expression is

21 is a rational number.
Fourth expression is

5 is a rational number.
Therefore, the correct options are 1, 3 and 4.