RBSE Solutions Class 9 Maths Chapter 10 Area of Triangles and Quadrilaterals Exercise 10.1

Question 1. Which of the following figures lie on the same base and between the same parallels? In such a case, write the common base and two parallels.
(ii)
(iii)
(iv)
(v)
(vi)
Answer:
(i) In figure (i), the figures share the same base DC and lie between the same parallel lines DC and AB. (ii) In figure (ii), the figures share the same base SR, but they are not located between the same parallel lines. (iii) In figure (iii), the figures share the same base PS and lie between the same parallel lines PS and QR. The shapes are properly aligned between these lines. (iv) In figure (iv), there is no common base shared by the different figures shown. (v) In figure (v), the figures share the same base AD and lie between the same parallel lines AD and BQ. (vi) In figure (vi), each individual part of the figure is placed on its own base, but all parts are situated between the same parallel lines SR and PQ.
In simple words: To check if figures share a base and parallel lines, look if they have one common side touching the same bottom line, and if their top points are all on another line that is parallel to the bottom one. If both are true, they meet the condition.

🎯 Exam Tip: When identifying common bases and parallel lines, ensure that the *entire* figure or figures are contained within the region defined by the parallel lines. The common base must be a shared side between the figures, not just a line that they sit on separately.