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Finding the Fourth Proportional to 615.90, 923.10 and 420.90

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Solution

The fourth proportional to 615.90, 923.10 and 420.90 is: 630.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    615.90 : 923.10 = 420.90 : x
  2. Step 2: Convert to fraction form
    615.90/923.10 = 420.90/x
  3. Step 3: Cross multiply
    615.90x = 923.10 × 420.90
  4. Step 4: Simplify right side
    615.90x = 388,532.79
  5. Step 5: Solve for x
    x = 388,532.79/615.90
  6. Step 6: Final answer
    x = 630.84

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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.