Page 89 - Start Up Mathematics_6

solve Mentally
True or False

1. A ray has definite length.
2. Three or more lines are said to be concurrent if each one of them intersects all the other lines.

3. Every closed figure formed by line segments may not be a polygon.
4. A minor segment contains the centre of the circle.
5. A chord of a circle is parallel to any one of its diameters.

6. The nearer a chord is to the centre of the circle, the greater is its length.
Fill in the Blanks

1. Two lines in a plane are either ____________ or ____________.
2. A polygon having least number of sides is a ____________.
3. The longest chord of the circle is ____________.

4. Given four intersecting lines, the minimum and maximum number of points of intersection
are ____________ and ____________ respectively.
5. A quadrilateral has ____________ sides.
6. The diameters of a circle are ____________.

7. Every point on a circle is ____________ from its centre.
Answer in One Word or a Line

1. What is a quadrant of a circle? How many quadrants are there in a circle?
2. Are all simple curves open?

3. What is a polygon? Name any three polygons having four sides.
4. Can three points on a circle be collinear?
5. What is the difference between a line, a line segment and a ray?

let’s evaluate
1. In a circle of radius r find each of the following:

(a) Length of the diameter
(b) The two parts in which the diameter divides the circle

(c) The region enclosed between two radii and an arc
2. State which of the following statements are true and which are false:

(a) If three or more lines pass through the same point, then the lines are concurrent.
(b) Only one line can be drawn from a point parallel to a given line.

(c) The radii of all concentric circles are equal.
(d) A triangle is a polygon having four sides.
(e) A simple curve can be either open or closed.

(f) Two lines in a plane are parallel if they do not intersect.

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