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Finding the Fourth Proportional to 787.42, 1,086.58 and 455.78

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Solution

The fourth proportional to 787.42, 1,086.58 and 455.78 is: 628.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.42 : 1,086.58 = 455.78 : x
  2. Step 2: Convert to fraction form
    787.42/1,086.58 = 455.78/x
  3. Step 3: Cross multiply
    787.42x = 1,086.58 × 455.78
  4. Step 4: Simplify right side
    787.42x = 495,243.01
  5. Step 5: Solve for x
    x = 495,243.01/787.42
  6. Step 6: Final answer
    x = 628.94

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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.