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Finding the Fourth Proportional to 840.64, 1,160 and 491.24

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Solution

The fourth proportional to 840.64, 1,160 and 491.24 is: 677.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.64 : 1,160 = 491.24 : x
  2. Step 2: Convert to fraction form
    840.64/1,160 = 491.24/x
  3. Step 3: Cross multiply
    840.64x = 1,160 × 491.24
  4. Step 4: Simplify right side
    840.64x = 569,838.40
  5. Step 5: Solve for x
    x = 569,838.40/840.64
  6. Step 6: Final answer
    x = 677.86

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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.