Question

Find the missing length of the given figure.

A. 6
B. 4
C. 2
D. 5

Answer 1

Hint: Here we use the concept of perimeter which is equal to the sum of all sides of a figure. We assume the length of the missing side as a variable and add the lengths of all sides. Equate the sum to the given perimeter and find the value of the variable.
* Perimeter is the sum of lengths of all sides. It is the boundary of any figure.

Complete step-by-step answer:
Here we are given a four sided figure with lengths 5cm, 4cm, 8cm.
Let us assume the length of the fourth side be xcm.
Then from the definition of parameter of a figure we can write the sum of given sides equal to the parameter.
\[ \Rightarrow \]Parameter \[ = \]5cm\[ + \]4cm\[ + \]8cm\[ + \]xcm
Add the values in right hand side of the equation.
\[ \Rightarrow \]Parameter \[ = (17 + x)\]cm
Substitute the value of parameter given in the statement of the question.
We are given parameter is 23cm
\[ \Rightarrow 23\]cm\[ = (17 + x)\]cm
Equate the numerical values on both sides of the equation
\[ \Rightarrow 23 = 17 + x\]
Shift all constant values to one side of the equation.
\[ \Rightarrow 23 - 17 = x\]
Calculate the difference in LHS of the equation.
\[ \Rightarrow 5 = x\]
So, the value of x is 5
\[\therefore \]Length of the missing side is 5cm

So, option D is correct.

Note: Students many times make mistakes while shifting values from one side of the equation to another side of the equation. Keep in mind the sign of the value changes from negative to positive and vice versa when shifting the values from one side of the equation to the other side of the equation.