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Finding the Fourth Proportional to 999.68, 1,376.78 and 978.14

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Solution

The fourth proportional to 999.68, 1,376.78 and 978.14 is: 1,347.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.68 : 1,376.78 = 978.14 : x
  2. Step 2: Convert to fraction form
    999.68/1,376.78 = 978.14/x
  3. Step 3: Cross multiply
    999.68x = 1,376.78 × 978.14
  4. Step 4: Simplify right side
    999.68x = 1,346,683.59
  5. Step 5: Solve for x
    x = 1,346,683.59/999.68
  6. Step 6: Final answer
    x = 1,347.11

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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.