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4. Find the measure of the angles formed between the minute hand and the hour hand of a clock at the QUADRILATERALS
following times:
a. 3 am b. 6 am c. 9 am d. 12 noon e. 3 pm QUADRILATERAL A simple closed.figure bounded byfour line segments is called a quadrilateral.

5. A man is facing east. In which direction will he be looking in each of these cases if he turns to the left by In the adjacent figure, ABCD is a quadrilateral.
a. one right angle b. two right angles c. three right angles d. four right angles A quadrilateral ABCD has:
e. one straight angle
(i) Four vertices, namely, A, B, C and D.
6. Classify each of the following triangles as scalene, isosceles or equilateral. (ii) Four sides, namely, AB, BC, CD and DA.
(iii) Four angles, namely, DAB, ABC, BCD and CDA, to be
denoted by A, B, C and LD respectively.
(iv) Two diagonals, namely, AC and BD.

ADJACENT SIDES Two sides of a quadrilateral which have a common end point are called its adjacent sides.

Thus, AB, BC; BC, CD; CD, DA, and DA, AB are four pairs of adjacent sides of the quadrilateral
ABCD.

OPPOSITE SIDES Two sides of a quadrilateral are called its opposite sides if they do not have a common end
point.

Thus, AB, DC, and AD, BC are two pairs of opposite sides of the quadrilateral ABCD.

ADJACENT ANGLES Two angles of a quadrilateral having a common side are called its adjacent angles.
Thus, A, B; B, C; C, D; and D, A are four pairs of adjacent angles of the quadrilateral ABCD.

OPPOSITE ANGLES Two angles of a quadrilateral which are not adjacent angles are known as the opposite
angles of the quadrilateral.
Thus, A, C, and B, D are two pairs of opposite angles of the quadrilateral ABCD.

REMARK The figure given below is also a figure obtained by joining four line segments
AB, BC, CD and DA But ABCD is not a quadrilateral, since these line segments
intersect at points other than their end points.

7. Check whether the three angles given will make a triangle. If so, classify them as acute, obtuse or right
triangles.

a. 30° , 30° , 120° b. 30° , 135° , 15° c. 60° , 30° , 90° d. 65° , 65° , 65°
e. 120° , 3° , 30° f. 45° , 45° , 90° g. 60° , 65° , 55 ° h. 60° , 60° , 60°
i. 20°, 30° , 40° j. 120° , 60°, 0°

8. The measures of the sides of some triangles are given below. Classify each triangle as scalene,
isosceles or equilateral.

a. 7 cm, 6 cm, 5 cm b. 6 cm, 6 cm, 6 cm c. 4 cm, 3 cm, 4 cm
d. 2 cm, 3 cm, 4 cm e. 5 cm, 6 cm, 6 cm

9. One of the equal angles of an isosceles triangle is 50° . Find its third angle.

10. Two angles of a triangle are 70° and 45° . Find the third angle.