What does diameter mean?
Word: Diameter
Part of Speech: Noun
Meaning: Diameter means the width of a circle or ball, measured straight across from one side to the other through its middle.
Word origin: From Greek diametros, through Latin and Old French.
How do you spell diameter?
Syllables: di - am - e - ter
Tricky part: British English writes metre for the unit of length, yet this word ends in meter, like thermometer. Students who know metre often write diametre.
Watch out for: diametre, diamater, diamiter
Memory tip: Measuring instruments such as the thermometer, barometer and speedometer all end the way diameter does; think of a diameter as another thing you measure.
Diameter in a sentence
Example 1: The pizza had a diameter of thirty centimetres, big enough for four of us.
Example 2: Siddharth used a ruler to draw the diameter of the circle for his maths homework.
Example 3: The giant wheel at the fair has a diameter of about forty metres.
Fun Fact
Measured across the equator, the Earth has a diameter of about 12,756 kilometres.
Practise the CREST Way
Jumble Tumble
What is the meaning of the word that can be formed from the given letters?
temriade
a) the distance all the way round the edge of a circle
b) a straight line from the centre of a circle to its edge
c) a straight line joining two sides of a circle and passing through its centre
d) the amount of flat space inside a closed shape
Show answer
c) a straight line joining two sides of a circle and passing through its centre. The letters make diameter, the line that crosses a circle through its centre.
Spell Probe
Spot the misspelt word in the sentence and choose its meaning:
To check the diameter of the old well, the engineers lowered a measuring tape and found it was wider than the new concreet pipe beside it.
a) a hard building material made from cement, sand, small stones and water
b) a long tube that carries water or gas
c) people who design and build roads, machines or bridges
d) a deep hole dug in the ground to reach water
Show answer
a) a hard building material made from cement, sand, small stones and water. Concrete has one e after the r and ends in te; diameter, engineers and measuring are spelt correctly.
Word Tally
Give 3 marks for each correctly spelt word. How many marks in all?
diameter, tangent, hexagon, isoceles, parralel
a) 12
b) 6
c) 15
d) 9
Show answer
d) 9. Isosceles hides an sc before its first e, and parallel has a single r and a double l in the middle; three words score 9 marks.
Sound Check
In which word is 'dia' pronounced differently?
a) India
b) diagram
c) dialect
d) diameter
Show answer
a) India. In diameter, diagram and dialect, dia begins with the sound of dye; in India it sounds like dee-a.
Multiple Choice Questions
1. A round table has a diameter of 120 cm. What is its radius?
a) 240 cm
b) 120 cm
c) 60 cm
d) 30 cm
Show answer
c) 60 cm
2. Which tool would you use to measure the diameter of a cricket ball accurately?
a) callipers
b) a set square
c) a spring balance
d) a protractor
Show answer
a) callipers
