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Finding the Fourth Proportional to 840.64, 1,260.72 and 320.64

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Solution

The fourth proportional to 840.64, 1,260.72 and 320.64 is: 480.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.64 : 1,260.72 = 320.64 : x
  2. Step 2: Convert to fraction form
    840.64/1,260.72 = 320.64/x
  3. Step 3: Cross multiply
    840.64x = 1,260.72 × 320.64
  4. Step 4: Simplify right side
    840.64x = 404,237.26
  5. Step 5: Solve for x
    x = 404,237.26/840.64
  6. Step 6: Final answer
    x = 480.87

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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.