Page 269 - Start Up Mathematics_6

4. There is only one line of symmetry in a 30°–60°–90° set square.

5. Perpendicular to a line from a given point not on it can be obtained by paper folding technique.
Fill in the Blanks
1. If image of points A and B in the line l are P and Q respectively then PQ is equal to _______.
2. To bisect a line segment of length 6 cm, the opening of the compass should be more than
_________.
3. If an angle of measure 60° is bisected twice, the angle so obtained measures ________.
4. In an isosceles ∆ ABC, the bisector of ∠B and ∠C meet at O. If ∠BOC = 140°, then ∠A
measures _____________.
5. The set squares are two triangular pieces having angles of _____________ and _____________
at their vertices.
Answer in One Word or a Line

1. How many arcs are required to be drawn to construct an angle of 60°?
2. How many circles can be drawn passing through two given points?
3. How many circles can pass through three collinear points?
4. Using two set squares of the geometry box, can you make an angle of 15°?
5. To bisect an angle, how many arcs are required to be drawn?

let’s evaluate
1. Draw a line segment measuring 8.2 cm and divide it into four equal parts using a ruler and
compass only.
2. Draw an angle of 50° using a protractor. Extend one of its arms to obtain its supplementary
angle. Copy this supplementary angle using a ruler and compass.
3. Draw an angle of measure 160° and divide it into four equal parts. Check your construction
by actual measurement.
4. Draw a square of side 7 cm using a ruler and compass only.

Thinking Skills

1. Draw any ∆ ABC. Through A, draw a line perpendicular to BC.
2. Draw a circle of radius 5 cm and divide it into six equal sectors

[Hint: Draw arcs cutting the circle with the opening of a compass equal to its radius.]
l
A
3. Mark the image of the point P in line l. Name it as P′.
Measure AP, BP, AP′, BP′. Is AP = AP′, BP = BP′?

P
B
4. Copy ∠AOB shown in the given figure. Using a ruler and B
1
compass, construct an angle equal to 2 times ∠AOB.
2 A
O
5. Draw any ∠AOB, such that OA = OB = 7 cm. Construct perpendicular bisectors of OA and
OB. Let them meet at P. Is PA = PB? Verify by actual measurement.

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