ONE-EIGHTH STAGE 2024
Accra Academy: 45 Points
Oyoko Methodist SHS: 36 points
St. Joseph Seminary SHS: 28 Points
ROUND 5 - RIDDLE
RIDDLE
You will find me inside a circle but I am not part of the circle.
I am often classified as major or minor.
ANSWER: SEGMENT
EXPLANATION:
A segment is the region between a chord and an arc.
It lies inside the circle and can be a major segment or a minor segment.
NOTE: A sector also lies inside a circle without being part of the circle itself, and it is also classified as major or minor, so these two clues fit a sector as well.
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PRACTICE QUESTIONS
1. RIDDLE:
I am a region of a circle.
I am bounded by two straight lines and a curve.
My two straight sides start at the same point.
I can be major or minor.
A slice of pizza has my shape.
My straight sides are two radii, and my area is $\dfrac{\theta}{360^\circ}\times\pi r^2$.
Who am I?
ANSWER: SECTOR
EXPLANATION:
A sector is the region between two radii and the arc joining their ends.
Its area is $\dfrac{\theta}{360^\circ}\times\pi r^2$, where $\theta$ is the angle at the centre.
2. RIDDLE:
I am a straight line segment.
I lie inside a circle.
Both my ends are on the circle.
A segment is bounded by me and an arc.
The perpendicular from the centre bisects me.
When I pass through the centre, I am the longest of my kind and am called a diameter.
Who am I?
ANSWER: CHORD
EXPLANATION:
A chord joins two points on a circle.
The perpendicular from the centre to a chord bisects it, and the longest chord is a diameter.
3. RIDDLE:
I am a straight line segment in a circle.
My ends lie on the circle.
I pass through the centre.
I cut the circle into two semicircles.
I am the longest chord.
I am twice the radius: $d = 2r$.
Who am I?
ANSWER: DIAMETER
EXPLANATION:
A diameter is a chord through the centre.
$d = 2r$, and it divides the circle into two semicircles.
4. RIDDLE:
I am part of a circle.
I am curved, not straight.
I join two points on the circle.
I can be major or minor.
My length is $\dfrac{\theta}{360^\circ}\times 2\pi r$.
I am a piece of the circumference.
Who am I?
ANSWER: ARC
EXPLANATION:
An arc is part of the circumference between two points on the circle.
Arc length $= \dfrac{\theta}{360^\circ}\times 2\pi r$
5. RIDDLE:
I am a straight line segment.
I start at the centre of a circle.
I end on the circle.
Every one of me in a circle has the same length.
A tangent is perpendicular to me at the point of contact.
I am half the diameter.
Who am I?
ANSWER: RADIUS
EXPLANATION:
A radius joins the centre to a point on the circle.
$r = \dfrac{d}{2}$
6. RIDDLE:
I am a length.
I belong to a circle.
I go all the way round.
Every arc is a part of me.
For a circle, I am the perimeter.
I am $2\pi r$ or $\pi d$.
Who am I?
ANSWER: CIRCUMFERENCE
EXPLANATION:
The circumference is the perimeter of a circle.
$C = 2\pi r = \pi d$