9th Grade > Mathematics
CONSTRUCTIONS MCQs
Total Questions : 56
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Answer: Option A. -> perpendicular bisector
:
A
Consider the above figure.
Here, XY is the perpendicular bisector of a line AB.
Let P be any random point on XY.
In △ PMA ≅ △ PMB
AM = BM (Perpendicular bisector divides a line segment into two equal halves)
∠ PMA =∠ PMB = 90∘
Also PM is common side
So △ PMA ≅ △ PMB (SASRule)
∴ PA = PB (CPCT)
Hence, △ PAB is an isosceles triangle.
So, the given statement is true.
:
A
Consider the above figure.
Here, XY is the perpendicular bisector of a line AB.
Let P be any random point on XY.
In △ PMA ≅ △ PMB
AM = BM (Perpendicular bisector divides a line segment into two equal halves)
∠ PMA =∠ PMB = 90∘
Also PM is common side
So △ PMA ≅ △ PMB (SASRule)
∴ PA = PB (CPCT)
Hence, △ PAB is an isosceles triangle.
So, the given statement is true.
Answer: Option C. -> 70 degrees
:
C
All the standard angles and the angles which can be obtained by bisecting standard angles can be constructed just by using a ruler and compass. Here except 70∘ all other angles can be constructed using ruler and compass.
:
C
All the standard angles and the angles which can be obtained by bisecting standard angles can be constructed just by using a ruler and compass. Here except 70∘ all other angles can be constructed using ruler and compass.
Answer: Option B. -> Two parallel lines
:
B
Since two parallel lines do not intersect each other, anangle cannotbe formed between them. Thus in this case, angle bisection is not possible.
:
B
Since two parallel lines do not intersect each other, anangle cannotbe formed between them. Thus in this case, angle bisection is not possible.
Answer: Option B. -> Rectangle
:
B
In the case of a rectangle, the diagonal is not an angle bisector.
Consider a rectangleABCD.
Here, ∠ ADB =∠ DBC (Alternate angles)
But,∠ DBC is not equal to∠ BDC (Angles opposite to unequal sides of a triangle are unequal)
∴∠ ADB is not equal to∠ BDC
So, diagonal DB does not bisect∠ D.
:
B
In the case of a rectangle, the diagonal is not an angle bisector.
Consider a rectangleABCD.
Here, ∠ ADB =∠ DBC (Alternate angles)
But,∠ DBC is not equal to∠ BDC (Angles opposite to unequal sides of a triangle are unequal)
∴∠ ADB is not equal to∠ BDC
So, diagonal DB does not bisect∠ D.
Answer: Option C. -> Line segment
:
C
A perpendicular bisector can be drawn only if a figure has end points. Only a line segment has a definite length and hence it can be bisected by a perpendicular bisector.
:
C
A perpendicular bisector can be drawn only if a figure has end points. Only a line segment has a definite length and hence it can be bisected by a perpendicular bisector.
Answer: Option C. -> Can't be determined
:
C
The information given above is insufficient to construct a triangle. So, the triangle cannot be constructed and its characteristics can’t be determined.
:
C
The information given above is insufficient to construct a triangle. So, the triangle cannot be constructed and its characteristics can’t be determined.
Answer: Option D. -> 10
:
D
In a triangle, the sum of thelengthsof any 2sidesof atrianglemust be greater than the thirdside. The third side can measure anything less than 11 units. Hence, the third side can be 10 units.
:
D
In a triangle, the sum of thelengthsof any 2sidesof atrianglemust be greater than the thirdside. The third side can measure anything less than 11 units. Hence, the third side can be 10 units.
:
The procedure for Triangle Construction 2 is:
1. Draw the base BC of ∆ABC as given and construct ∠XBC of the required measure at B as shown.
2. From the ray, BX cut an arc equal to AB – AC at point P and join it to C as shown
3. Draw the perpendicular bisector of PC and let it intersect BX at point A as shown:
4. Join AC, ∆ABC is the required triangle.
Hence, it is clear that a perpendicular bisector is required in the process.