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Finding the Fourth Proportional to 978.60, 1,409.76 and 978.60

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Solution

The fourth proportional to 978.60, 1,409.76 and 978.60 is: 1,409.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.60 : 1,409.76 = 978.60 : x
  2. Step 2: Convert to fraction form
    978.60/1,409.76 = 978.60/x
  3. Step 3: Cross multiply
    978.60x = 1,409.76 × 978.60
  4. Step 4: Simplify right side
    978.60x = 1,379,591.14
  5. Step 5: Solve for x
    x = 1,379,591.14/978.60
  6. Step 6: Final answer
    x = 1,409.76

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Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.