Question

Express the following as cm using decimals.
             (a) 30mm

Answer 1

Hint: We will use the concept of Units and measurement. We will be using a conversion formula of m to cm, m to mm. By using these formulas we can convert from mm to cm or cm to mm.

Complete step-by-step solution -
We have to convert 30mm into cm. We can write 30mm:
30mm=30$\times $1mm
Now to convert it into cm we need to find the conversion formula of 1mm to cm.
We know that
1m=100cm ……. (1)
Also,
1m=1000mm …… (2)
From (1) and (2) we get
100cm=1000mm
So, on simplifying it we get
1cm=10mm
Or we can rewrite it as:
1mm =$\dfrac{1}{10}$cm …. (3)
Now we will be using (3) to convert 30mm to cm
30mm=30$\times $1mm
=30$\times $$\dfrac{1}{10}$cm
=3cm
Hence the answer is 3cm.

Note: In these types of questions we have to use the concepts of units and measurement. To solve these types of problems we need to know the conversion formula of 1m to cm, 1m to mm, etc depending on what has been asked in the question. So, remembering these are necessary to solve these types of questions. Also, calculation mistakes are very common in these types of questions so that should also be taken into consideration while performing the conversion.