10.2.1 Circles I, PT3 Focus Practice
Diagram below shows a circle with centre O.
The radius of the circle is 35 cm.
Calculate the length, in cm, of the major arc AB.
Angle of the major arc AB = 360o – 144o= 216o
In diagram below, O is the centre of the circle. SPQ and POQ are straight lines.
The length of PO is 8 cm and the length of POQ is 18 cm.
Calculate the length, in cm, of SPT.
Radius = 18 – 8 = 10 cm
PT2 = 102 – 82
= 100 – 64
PT = 6 cm
Length of SPT = 6 + 6
= 12 cm
Diagram below shows two circles. The bigger circle has a radius of 14 cm with its centre at O.
The smaller circle passes through O and touches the bigger circle.
Calculate the area of the shaded region.
Diagram below shows two sectors. ABCD is a quadrant and BED is an arc of a circle with centre C.
Calculate the area of the shaded region, in cm2.
Diagram below shows a square KLMN. KPN is a semicircle with centre O.
Calculate the perimeter, in cm, of the shaded region.
Perimeter of the shaded region
= KL + LM + MN + NP + Arc length PK
= 14 + 14 +14 + 9.90 + 11= 62.90 cm