Home / 128,721.72-177,640.80-72,131

Finding the Fourth Proportional to 128,721.72, 177,640.80 and 72,131

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Solution

The fourth proportional to 128,721.72, 177,640.80 and 72,131 is: 99,543.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    128,721.72 : 177,640.80 = 72,131 : x
  2. Step 2: Convert to fraction form
    128,721.72/177,640.80 = 72,131/x
  3. Step 3: Cross multiply
    128,721.72x = 177,640.80 × 72,131
  4. Step 4: Simplify right side
    128,721.72x = 12,813,408,544.80
  5. Step 5: Solve for x
    x = 12,813,408,544.80/128,721.72
  6. Step 6: Final answer
    x = 99,543.48

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.