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Finding the Fourth Proportional to 459.80, 689.70 and 420.92

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Solution

The fourth proportional to 459.80, 689.70 and 420.92 is: 631.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    459.80 : 689.70 = 420.92 : x
  2. Step 2: Convert to fraction form
    459.80/689.70 = 420.92/x
  3. Step 3: Cross multiply
    459.80x = 689.70 × 420.92
  4. Step 4: Simplify right side
    459.80x = 290,308.52
  5. Step 5: Solve for x
    x = 290,308.52/459.80
  6. Step 6: Final answer
    x = 631.38

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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.