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Finding the Fourth Proportional to 978.01, 1,349.47 and 628.65

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Solution

The fourth proportional to 978.01, 1,349.47 and 628.65 is: 867.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.01 : 1,349.47 = 628.65 : x
  2. Step 2: Convert to fraction form
    978.01/1,349.47 = 628.65/x
  3. Step 3: Cross multiply
    978.01x = 1,349.47 × 628.65
  4. Step 4: Simplify right side
    978.01x = 848,341.17
  5. Step 5: Solve for x
    x = 848,341.17/978.01
  6. Step 6: Final answer
    x = 867.42

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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.