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Finding the Fourth Proportional to 923.80, 1,385.70 and 486.40

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Solution

The fourth proportional to 923.80, 1,385.70 and 486.40 is: 729.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    923.80 : 1,385.70 = 486.40 : x
  2. Step 2: Convert to fraction form
    923.80/1,385.70 = 486.40/x
  3. Step 3: Cross multiply
    923.80x = 1,385.70 × 486.40
  4. Step 4: Simplify right side
    923.80x = 674,004.48
  5. Step 5: Solve for x
    x = 674,004.48/923.80
  6. Step 6: Final answer
    x = 729.60

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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.