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Form 4 Mathematics
Basic terms of a circle
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Circle OP is a line segment of fixed length. Click the button "Animate" to see the path of P. A circle is the locus of a point P which moves at fixed distance from a fixed point O, called the centre. Click the red "X" at the lower-right corner to erase the locus. |
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A way to trace a circle AB is a fixed line segemnt. AQC is a line passing through A. BQ is a line perpendicular to AQC. Drag C to view the path of Q. You may also click the button "Animate". What is the measure of angle AQB? Click the red "X" at the lower-right corner to erase the locus. |
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Drag the points P and Q. Can the chord PQ become a diameter? When will the length of the chord PQ be maximum? |
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Concentric circles Click on the button "Concentric circles". The two circles are called concentric circles. Drag O, B, C and observe. Explain the meaning of concentric circles in own words |
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Equal circles Click on the button "Equal circles". The two circles are called equal circles. Vary the length of AB and observe. Explain the meaning of equal circles in own words |
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Inscribed Quadrilateral Click on the button "Inscribed Quadrilateral". ABCD is an inscribed quadrilateral. We say that ABCD is inscribed in the circle. Explain the meaning of inscribed quadrilateral in own words. Is the circle inscribed in triangle ABC? Is triangle ABC inscribed in the circle? |
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Question ABC is a triangle inscribed in a circle with centre O. Draw a diagram on a paper showing the information. Check your answer with the diagram on the right by clicking the "Answer" button. |
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Question A circle is incribed in a triangle ABC . Draw a diagram on a paper showing the information. Check your answer with the diagram on the right by clicking the "Answer" button. |
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Circumcircle Click on the button "Circumcircle of ABCD". The circle is called a circumcircle of ABCD. We say the circle is circumscribed about ABCD. Explain the meaning of circumcircle in own words. Is the circle circumscribed about triangle ABC? Is triangle ABC circumscribed about the circle? |
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Questions Which of the following have the same meaning in a diagram (i.e. equivalent)? (1) ABCD is inscribed in the circle. (2) The circle is inscribed in ABCD. (3) ABCD is circumscribed about the circle. (4) The circle is circumscribed about ABCD. |
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