Page 214 - Start Up Mathematics_7

5. A unique triangle cannot be constructed with which of the following sets of measurements? A D

(a) three sides (b) three angles and one side
(c) two angles and an included side (d) the hypotenuse and a leg

6. The maximum number of points at which 4 lines can intersect is: B C E F
(a) 3 (b) 4 (c) 6 (d) 10

7. The number of line segments that can be formed using 4 collinear points:
(a) 3 (b) 4 (c) 6 (d) unlimited
8. A triangle of sides measuring p, q and r units is always possible if:

(a) p + q > r (b) p + q = r T S
(c) p + q < r (d) none of these R

9. The number of pairs of adjacent angles in the adjoining figure are: Q
(a) 3 (b) 5 (c) 9 (d) 10 O P

solve Mentally
True or False

1. A unique triangle with sides measuring 7 cm, 8.1 cm and 9.3 cm cannot be constructed.
2. A unique triangle with angles measuring 60°, 1° and 119° can be constructed.
3. Four lines in a plane can intersect at 3 points.

4. Four lines in a plane can intersect at 5 points.
5. A unique triangle can be constructed with measures corresponding to SAS construction
criterion.
6. A unique triangle can be constructed with measures corresponding to AAS construction
criterion.
7. An acute angle and length of hypotenuse is sufficient to construct a right triangle.

8. We can use a ruler and compass only to draw a line parallel to a given line from a point
outside it. A
9. In a triangle the angle opposite the largest side is the smallest.

10. A ∆ ABC whose dimension are shown in the given figure can 7 cm 6 cm
be uniquely constructed, i.e., SSA construction criterion is valid. 35°
B C
Fill in the Blanks

1. If two angles of a triangle are unequal, then the side opposite P
the angle which is ____________ is longer. 100° 1 l
2. If a line l is parallel to the side PQ of a triangle as shown then, 40° 40°
∠1 = ____________. Q R

3. A point on the perpendicular bisector of a segment is
____________ from the end points of the segment.

4. The _______________ of a line segment is obtained by joining the points of intersections of
a pair of arcs on either side of the line segment drawn from its end points.

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