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Finding the Fourth Proportional to 787.13, 1,085.78 and 455.50

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Solution

The fourth proportional to 787.13, 1,085.78 and 455.50 is: 628.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.13 : 1,085.78 = 455.50 : x
  2. Step 2: Convert to fraction form
    787.13/1,085.78 = 455.50/x
  3. Step 3: Cross multiply
    787.13x = 1,085.78 × 455.50
  4. Step 4: Simplify right side
    787.13x = 494,572.79
  5. Step 5: Solve for x
    x = 494,572.79/787.13
  6. Step 6: Final answer
    x = 628.32

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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.