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Activity on Ratio proportion (view source)
Revision as of 17:34, 14 February 2014
, 17:34, 14 February 2014Created page with "==Ratio and Proportionality= ==Exercise 2.4.2== In the adjacent figure, two triangles are similar. Find the length of the missing side This problem can be solved with the foll..."
==Ratio and Proportionality=
==Exercise 2.4.2==
In the adjacent figure, two triangles are similar. Find the length of the missing side
This problem can be solved with the following steps.
#Prerequisites: students should know the concept of similarity and proportionality
Proportionality : two ratios are equal then four quantities are in proportional
Similar Triangles : If two triangles are said to be similar 1. if they are equiangular 2. the corresponding side are proportional
# Understanding/ analysing the given problem
## Identifying/ Naming the triangles
## Identifying the sides whose lemgth is not given
## comparing two sides of triangles (visualising that 1st triangle is smaller than 2 nd triagle and viceversa
## should identify the corresponding sides (sides having same allignment)
# Procedure
## find the ratio between the corresponding sides whose length is known <math>13 / 39 = 13 * 1 / 13 *3 = 1/3</math>
## express proportional corresponding sides (using the property of similarity)
AC/DF = AB/DE
13/39 = 5/x
13 : 39 = 5 : x (use the property of proportionality i.e Product of extremes is equal to product of means)
13 * x = 39 * 5
x = 39* 5 /13
x = 15 cms
==Exercise 2.4.2==
In the adjacent figure, two triangles are similar. Find the length of the missing side
This problem can be solved with the following steps.
#Prerequisites: students should know the concept of similarity and proportionality
Proportionality : two ratios are equal then four quantities are in proportional
Similar Triangles : If two triangles are said to be similar 1. if they are equiangular 2. the corresponding side are proportional
# Understanding/ analysing the given problem
## Identifying/ Naming the triangles
## Identifying the sides whose lemgth is not given
## comparing two sides of triangles (visualising that 1st triangle is smaller than 2 nd triagle and viceversa
## should identify the corresponding sides (sides having same allignment)
# Procedure
## find the ratio between the corresponding sides whose length is known <math>13 / 39 = 13 * 1 / 13 *3 = 1/3</math>
## express proportional corresponding sides (using the property of similarity)
AC/DF = AB/DE
13/39 = 5/x
13 : 39 = 5 : x (use the property of proportionality i.e Product of extremes is equal to product of means)
13 * x = 39 * 5
x = 39* 5 /13
x = 15 cms
