Question

Help me plz it's the first time using it

Answer 1

This whole problem rests on one thing:
Do you know the formula for the volume of this kind of shape ?
If you do, then the problem is easy.  If you don't, then it's impossible.

This is the shape of a book, an ice cube, a brick, or a slab.

The volume is always

                          (length) x (width) x (height)           (in any order) .

They all have to be in the same unit, and then the volume
is in the cubic-(...) of that unit.

In this picture, there's a tiny hiccup with the units ... the length and
the width are in meters, but the height is in centimeters, so you need
to change that one to meters before you can multiply them.

Notice right above the picture, it reminds you that 

                                         (1 meter = 100 centimeters) .

So the height of the slab (10 cm) is the same as 0.1 meter.

Now you have all 3 of the dimensions in meters, so you're
ready to multiply them and get the volume.

           Volume  =  (length) x (width) x (height) 

                         =  ( 8 m )  x  ( 6 m )  x  ( 0.1 m )

                         =            4.8 cubic meters .

Question: 
Does Meg have enough concrete to make the slab
with the dimensions shown ?

Answer:  Yes .

Explanation:
Meg mixed 5 cubic meters of concrete.
She needs 4.8 cubic meters to pour the floor with those dimensions.
She has enough concrete to do the job.
All she needs is the whole football team to come over and help her
     pour, smooth, and finish it.  Concrete is hard hard work !