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Finding the Fourth Proportional to 840.69, 1,261.53 and 430.20

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Solution

The fourth proportional to 840.69, 1,261.53 and 430.20 is: 645.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.69 : 1,261.53 = 430.20 : x
  2. Step 2: Convert to fraction form
    840.69/1,261.53 = 430.20/x
  3. Step 3: Cross multiply
    840.69x = 1,261.53 × 430.20
  4. Step 4: Simplify right side
    840.69x = 542,710.21
  5. Step 5: Solve for x
    x = 542,710.21/840.69
  6. Step 6: Final answer
    x = 645.55

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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.