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Finding the Fourth Proportional to 840.80, 1,260.16 and 407.84

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Solution

The fourth proportional to 840.80, 1,260.16 and 407.84 is: 611.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.80 : 1,260.16 = 407.84 : x
  2. Step 2: Convert to fraction form
    840.80/1,260.16 = 407.84/x
  3. Step 3: Cross multiply
    840.80x = 1,260.16 × 407.84
  4. Step 4: Simplify right side
    840.80x = 513,943.65
  5. Step 5: Solve for x
    x = 513,943.65/840.80
  6. Step 6: Final answer
    x = 611.26

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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.