What does perimeter mean?
Word: Perimeter
Part of Speech: Noun
Meaning: Perimeter means the total length of the edge around a flat shape or an area. In maths, you find it by adding up the lengths of all the sides.
Synonyms: boundary, border
Word origin: From Greek perimetros, through Latin; the Greek word described a measurement taken all the way round something.
How do you spell perimeter?
Syllables: pe - rim - e - ter
Tricky part: Unlike centimetre and kilometre, perimeter ends in er, not re: it is a distance round a shape, not a unit of length, so British English keeps the er spelling, as it does for diameter.
Watch out for: perimetre, perimiter, perimter
Memory tip: The perimeter is the outer line of a shape, and outer and perimeter finish with the same two letters, e and r.
Perimeter in a sentence
Example 1: Tara walked the perimeter of the park twice every evening, which came to about two kilometres.
Example 2: In the maths test, we had to find the perimeter of a triangle with sides of 7, 8 and 9 cm.
Example 3: The farmer planted a row of neem trees along the perimeter of his field.
Fun Fact
Of all flat shapes with the same perimeter, a circle encloses the most area, which is one reason why many storage tanks and grain bins are round.
Practise the CREST Way
Word Twins
Read both sentences and choose the correct option:
1. The scouts jogged round the perimeter of the campsite before breakfast. 2. Wind speed is one perimeter that the weather station records every hour.
a) both
b) neither
c) only 2
d) only 1
Show answer
d) only 1. Sentence 2 needs parameter, a factor that can be measured; perimeter is the distance round the edge of a shape.
Word Champ
Read the statements and choose the correct option:
1. The perimeter of a square with sides of 6 cm is 24 cm. 2. The perimeter of a rectangle 5 m long and 3 m wide is 15 m. 3. The perimeter of a circle is called its circumference.
a) both 2 and 3
b) both 1 and 3
c) all three
d) both 1 and 2
Show answer
b) both 1 and 3. A 5 m by 3 m rectangle measures 5 + 3 + 5 + 3 = 16 m round its edge, so statement 2 is false.
Spellacadabra
Choose the option in which the following letters will fit in the given order:
e, i
a) m__n__ster
b) p__r__meter
c) s__l__nce
d) c__l__ndar
Show answer
b) p__r__meter. Perimeter takes e and then i; silence takes i then e, minister i twice, and calendar a then e.
Spell Spies
Choose the pair which has a spelling error:
a) vertex : vertices
b) perimeter : perimeters
c) axis : axies
d) matrix : matrices
Show answer
c) axis : axies. The plural of axis is axes: the i of the singular turns into e, and no extra letter is added.
Multiple Choice Questions
1. To put a fence round a rectangular garden, which measurement do you need?
a) the distance round its edge
b) the height of its tallest tree
c) the space its soil covers
d) the depth of its garden well
Show answer
a) the distance round its edge
2. Security lights were placed along the perimeter of the stadium. Where were they placed?
a) under the rows of seats
b) around its outer edge
c) on the roof of the main stand
d) in the middle of the pitch
Show answer
b) around its outer edge
