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Finding the Fourth Proportional to 615.30, 921.60 and 431.70

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Solution

The fourth proportional to 615.30, 921.60 and 431.70 is: 646.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    615.30 : 921.60 = 431.70 : x
  2. Step 2: Convert to fraction form
    615.30/921.60 = 431.70/x
  3. Step 3: Cross multiply
    615.30x = 921.60 × 431.70
  4. Step 4: Simplify right side
    615.30x = 397,854.72
  5. Step 5: Solve for x
    x = 397,854.72/615.30
  6. Step 6: Final answer
    x = 646.60

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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.