This document discusses concepts related to calculating volumes, surface areas, and water depth. It provides examples of calculating the volume of boxes and blocks using length, width, and height. It also discusses how the volume of water remains the same when poured from a bottle onto a surface, and provides a multi-step example of calculating water depth over a field by determining the volume of water from a reservoir and the surface area of the field.

2.  How many apple in 1 dozen of
apple?
 Haw many 1 peso in 100 pesos?

5.  It may be necessary to determine
the surface area of a farmer's
field.
 For example, when calculating
how much irrigation water
should be given to a certain
field, the size of the field must
be known.

6.  Given Length of the field =50 m
Width of the field = 30 m
 Formula: A = length x width
 = 50 m x 30 m
 = 1500 m2

7.  A hectare is equal to 10 000 m.
 Surface area in hectares (ha)= surface
area in square meters(m2) / 10 000

8.  A volume (V) is the content of a
body or object.
 Take for example a box.
 A box has a certain length (l), width
(w) and height (h).
 With these three data, the volume of
the box can be calculated using the
formula:

9.  Formula: V = length x width x height
 Given length =4 cm, width =3 cm , height =2 cm

10.  The volume of this block is
expressed in cubic centimeters
(written as cm).
 Volumes can also be
expressed in cubic decimeters
(dm3), cubic meters (m3), etc.

11.  Calculate the volume in m3 of a
block with a length of 4 m, a
width of 50 cm and a height of
200 mm.
 All data must be converted in
meters (m)

12. Calculate the volume of the
same block, this time in cubic
centimeters (cm3)
All data must be converted in
centimeters (cm)

13.  Suppose a one-liter bottle is filled
with water. The volume of the water
is 1 liter . When the bottle of water is
emptied on a table, the water will
spread out over the table and form a
thin water layer.

14.  What happen to the amount of water?
 Was it the same as the amount of water in
the bottle?
 The volume of water remains the same
 Only the shape of the "water body" changes.

15. One liter of water spread
over a table
A similar process happens
if you spread irrigation
water from a storage
reservoir over a farmer's
field.

16.  Suppose there is a reservoir, filled
with water, with a length of 5 m, a
width of 10 m and a depth of 2 m.
 All the water from the reservoir is
spread over a field with a length of
100m and width 100m
 Calculate the water depth (which is
the thickness of the water layer) on
the field.

17.  The formula to use is:
 Water depth (d) = Volume of water (V)
Surface of the field (A)

18.  As the first step, the volume of water must be
calculated. It is the volume of the filled
reservoir
 Volume (V) = length x width x height
 = 5 m x 10 m x 2 m
 = 100 m3

19.  second step, the area of the field
must be calculated.
 Formula: A = length x width
 = 100 m x 100 m
 = 10 000 m2

20.  Third step, the thickness of the
water layer is calculated using
formula
 Water depth (d) = Volume of water (V)
Surface of the field (A)
 = 100 m3
 10 000 m2
 d = 0.01 m
 d = 10 mm