Let us study the following examples- (i) (2+3)+4
2 +(3+4)
5+ 4
= 2 + 7
9
= 9
(ii) (-2+3) + 5
-2 + (3 + 5
1 + 5
= 2 + 8
6
6
(iii) (-2 + 3) + (-5) = (-2) + [3 + (-5)]
= (-2) + (-2)
4
1 +(-5)
-4
(iv) [(-2)+(-3)] + (-5)
-5+(-5)
-2 + [(-3) + (-5)]
-2+(-8)
-10
= -10
VII CLASS MATHEMATICS

He trapezoid is composed of a rectangle and two triangles. what is the area of the rectangle? what is the total area of the triangles? what is the area of the trapezoid? ? a) 42 cm2; 27 cm2; 69 cm 2 b) 54 cm2; 27 cm2; 81 cm 2 c) 108 cm2; 27 cm2; 135 cm 2 d) 108 cm2; 13.5 cm2; 121.5 cm 2