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.
Volume of a square pyramid when the area of the base is known is area x height/3
Volume = 48 x 8/3 = 128 cubic cm.
Answer:
a
Step-by-step explanation:
Answer:
90°
Step-by-step explanation:
Interior angles of ALL triangles sum to 180°
The whole large triangle has angles 60 60 60 ( they sum to 180)
that means x = 30
then the small triangle on the right has 60 + 30 + y = 180
meaning y = 90 °
Answer:
with what do u need help with?