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Finding the Fourth Proportional to 642.40, 886.40 and 477.60

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Solution

The fourth proportional to 642.40, 886.40 and 477.60 is: 659.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.40 : 886.40 = 477.60 : x
  2. Step 2: Convert to fraction form
    642.40/886.40 = 477.60/x
  3. Step 3: Cross multiply
    642.40x = 886.40 × 477.60
  4. Step 4: Simplify right side
    642.40x = 423,344.64
  5. Step 5: Solve for x
    x = 423,344.64/642.40
  6. Step 6: Final answer
    x = 659.00

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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.