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Finding the Fourth Proportional to 840.42, 1,159.70 and 491.31

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Solution

The fourth proportional to 840.42, 1,159.70 and 491.31 is: 677.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.42 : 1,159.70 = 491.31 : x
  2. Step 2: Convert to fraction form
    840.42/1,159.70 = 491.31/x
  3. Step 3: Cross multiply
    840.42x = 1,159.70 × 491.31
  4. Step 4: Simplify right side
    840.42x = 569,769.75
  5. Step 5: Solve for x
    x = 569,769.75/840.42
  6. Step 6: Final answer
    x = 677.96

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.