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Finding the Fourth Proportional to 1,285.68, 1,924.68 and 978.72

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Solution

The fourth proportional to 1,285.68, 1,924.68 and 978.72 is: 1,465.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.68 : 1,924.68 = 978.72 : x
  2. Step 2: Convert to fraction form
    1,285.68/1,924.68 = 978.72/x
  3. Step 3: Cross multiply
    1,285.68x = 1,924.68 × 978.72
  4. Step 4: Simplify right side
    1,285.68x = 1,883,722.81
  5. Step 5: Solve for x
    x = 1,883,722.81/1,285.68
  6. Step 6: Final answer
    x = 1,465.16

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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.