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Finding the Fourth Proportional to 865.40, 1,298.10 and 814.10

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Solution

The fourth proportional to 865.40, 1,298.10 and 814.10 is: 1,221.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.40 : 1,298.10 = 814.10 : x
  2. Step 2: Convert to fraction form
    865.40/1,298.10 = 814.10/x
  3. Step 3: Cross multiply
    865.40x = 1,298.10 × 814.10
  4. Step 4: Simplify right side
    865.40x = 1,056,783.21
  5. Step 5: Solve for x
    x = 1,056,783.21/865.40
  6. Step 6: Final answer
    x = 1,221.15

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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.