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Spell Bee Word: radius


Basic Details

Word: Radius

Part of Speech: Noun

Meaning: A straight line from the centre of a circle to its edge, or the length of that line. It is also the name of a bone in the forearm.

How to Spell Radius

Syllables: ra - di - us

Tricky part: The ending is ius, not ious or eus. The plural is usually radii, said ray-dee-eye.

Watch out for: raduis, radeus, raddius

Memory tip: Radius begins just like radio: rad-i. Then swap the o of radio for us.

Usage Examples

Example 1: The radius of the wheel is 30 centimetres.

Example 2: Phone towers cover a radius of several kilometres.

Example 3: Use a compass to draw a circle with a radius of 4 cm.

Fun Fact

The radius in your arm is the bone on the thumb side of the forearm. It turns around the ulna when you twist your wrist.

Practise the CREST Way

Word Cookie

Find the extra letter in the word:

raddius

a) s
b) i
c) r
d) d

Show answer

d) d. Radius has a single d, as radio does.

Spell-o-Spell

Choose the meaning of the correctly spelt word:

1. tangant 2. circumferance 3. diamater 4. radius

a) the distance from the centre of a circle to its edge
b) a line that touches a curve at just one point
c) the distance all the way round a circle
d) a straight line across a circle through its centre

Show answer

a) the distance from the centre of a circle to its edge. Diameter has an e after the m, circumference ends in ence, and tangent ends in ent.

Mingle-Mangle

Unjumble the letters in the sentence and choose the word they make:

Draw a circle with a sudari of five centimetres in your notebook.

a) radius
b) raised
c) radish
d) radios

Show answer

a) radius. Radish has an h, radios an o, and raised an e; only radius uses the u in the jumble.

Multiple Choice Questions

1. If the radius of a circle is 4 cm, its diameter is ____.

a) 4 cm
b) 2 cm
c) 8 cm
d) 16 cm

Show answer

c) 8 cm

2. Shops within a two-kilometre radius of the school are ____.

a) on the school roof
b) in another city
c) exactly 4 km away
d) no more than 2 km away

Show answer

d) no more than 2 km away

Associated Words

parenthesisstewardessdetrimentalpersonalexorbitant
distinctionreciprocalacquiescephonographoverwhelmed

Next steps

How to participate in CREST International Spell Bee

The CREST International Spell Bee (CSB) is conducted in two editions – CREST International Spell Bee - Summer (CSB) and CREST International Spell Bee - Winter (CSBW) – giving students across the globe an opportunity to showcase and enhance their spelling proficiency. Designed for young learners from Senior KG to Class 8, the competition focuses on word-building, pronunciation, and vocabulary enrichment, helping students develop strong linguistic skills.

Steps to Participate:

Step 1: Visit the registration page and complete the registration with your desired subject.

Step 2: After Registration done, do login at www.crestolympiads.com/login.

Step 3: After login, go to dashboard and click on Book slot/Take Exam

Step 4: Schedule your exam date and preferred time.

Step 5: Log in with your credentials on the exam day at the scheduled time and take the exam.

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