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Finding the Fourth Proportional to 923.40, 1,385.10 and 811.80

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Solution

The fourth proportional to 923.40, 1,385.10 and 811.80 is: 1,217.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    923.40 : 1,385.10 = 811.80 : x
  2. Step 2: Convert to fraction form
    923.40/1,385.10 = 811.80/x
  3. Step 3: Cross multiply
    923.40x = 1,385.10 × 811.80
  4. Step 4: Simplify right side
    923.40x = 1,124,424.18
  5. Step 5: Solve for x
    x = 1,124,424.18/923.40
  6. Step 6: Final answer
    x = 1,217.70

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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.