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Finding the Fourth Proportional to 432.50, 648.75 and 128.50

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Solution

The fourth proportional to 432.50, 648.75 and 128.50 is: 192.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.50 : 648.75 = 128.50 : x
  2. Step 2: Convert to fraction form
    432.50/648.75 = 128.50/x
  3. Step 3: Cross multiply
    432.50x = 648.75 × 128.50
  4. Step 4: Simplify right side
    432.50x = 83,364.38
  5. Step 5: Solve for x
    x = 83,364.38/432.50
  6. Step 6: Final answer
    x = 192.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.