On the same base and with the same altitude, consider a parallelogram (area P), a triangle (area R), and a rectangle (area A).\nWhich relation is always true?

Introduction / Context:
For plane figures sharing the same base length b and altitude h, their areas follow standard formulas: parallelogram P = b*h, rectangle A = b*h, triangle R = (1/2)*b*h. Comparing these immediately yields the fixed relations among P, A, and R.

Given Data / Assumptions:

• All figures share base b and altitude h.

Concept / Approach:
Write each area in terms of b and h and compare.

Step-by-Step Solution:

Why Other Options Are Wrong:

• P=R: False; triangle area is half.
• P=A/2: False; parallelogram equals rectangle, not half.

Final Answer:
P=2R