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Finding the Fourth Proportional to 978.77, 1,351.07 and 647.65

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Solution

The fourth proportional to 978.77, 1,351.07 and 647.65 is: 894.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.77 : 1,351.07 = 647.65 : x
  2. Step 2: Convert to fraction form
    978.77/1,351.07 = 647.65/x
  3. Step 3: Cross multiply
    978.77x = 1,351.07 × 647.65
  4. Step 4: Simplify right side
    978.77x = 875,018.73
  5. Step 5: Solve for x
    x = 875,018.73/978.77
  6. Step 6: Final answer
    x = 894.00

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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.