Area of a sector
The Maths Habit
A sector has radius 9 cm and angle 80°. Find its arc length to 1 decimal place.
12.6 cmA circle has diameter 20 m. Find the length of a 270° arc of it, to 1 decimal place.
47.1 mA sector has radius 4.5 cm and angle 150°. Find its arc length to 1 decimal place.
11.8 cm
One sprinkler turns through a quarter turn and reaches 6 m. Another turns through a half turn and reaches 4 m. Which waters more lawn?
The quarter turn: about 28.3 m² of lawn against 25.1 m².
What fraction of the circle is this?
The diameter is 18 cm.
What is the radius?
9 cm
- Sector
- A slice of a circle, between two radii and an arc.
Sector area = fraction of the circle × area of the circle
Find the area of the sector to 1 decimal place.
Find the area of the sector to 1 decimal place.
Area =60360fraction of the circle
× π × Answer18.8cm2
Area =40360fraction of the circle
× π × Answer50.3cm2
Area =60360fraction of the circle
× π × Answer18.8cm2
Area =135360fraction of the circle
× π × Answer75.4cm2
Area =60360fraction of the circle
× π × Answer18.8cm2
Area =72360fraction of the circle
× π × Answer15.7cm2
Area =60360fraction of the circle
× π × Answer18.8cm2
Area =240360fraction of the circle
× π × Answer33.5cm2
Area =60360fraction of the circle
× π × Answer18.8cm2
Area =150360fraction of the circle
× π × Answer130.9cm2
A sector has an angle of 90° and an area of 25π cm2. What is its radius?
10 cmWhich is bigger: a quarter of a circle with radius 6 cm, or half of a circle with radius 4 cm?
The quarter
Find the area to 1 decimal place.
25.1 cm2Find the area to 1 decimal place.
63.3 cm2A circle has a diameter of 14 cm. Find the area of a 140° sector of it to 1 decimal place.
59.9 cm2
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