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Finding the Fourth Proportional to 714.62, 1,070.40 and 421.80

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Solution

The fourth proportional to 714.62, 1,070.40 and 421.80 is: 631.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.62 : 1,070.40 = 421.80 : x
  2. Step 2: Convert to fraction form
    714.62/1,070.40 = 421.80/x
  3. Step 3: Cross multiply
    714.62x = 1,070.40 × 421.80
  4. Step 4: Simplify right side
    714.62x = 451,494.72
  5. Step 5: Solve for x
    x = 451,494.72/714.62
  6. Step 6: Final answer
    x = 631.80

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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.