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Finding the Fourth Proportional to 840.26, 1,259.76 and 429.20

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Solution

The fourth proportional to 840.26, 1,259.76 and 429.20 is: 643.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.26 : 1,259.76 = 429.20 : x
  2. Step 2: Convert to fraction form
    840.26/1,259.76 = 429.20/x
  3. Step 3: Cross multiply
    840.26x = 1,259.76 × 429.20
  4. Step 4: Simplify right side
    840.26x = 540,688.99
  5. Step 5: Solve for x
    x = 540,688.99/840.26
  6. Step 6: Final answer
    x = 643.48

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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.