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Finding the Fourth Proportional to 865.65, 1,298.18 and 280.49

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Solution

The fourth proportional to 865.65, 1,298.18 and 280.49 is: 420.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.65 : 1,298.18 = 280.49 : x
  2. Step 2: Convert to fraction form
    865.65/1,298.18 = 280.49/x
  3. Step 3: Cross multiply
    865.65x = 1,298.18 × 280.49
  4. Step 4: Simplify right side
    865.65x = 364,125.81
  5. Step 5: Solve for x
    x = 364,125.81/865.65
  6. Step 6: Final answer
    x = 420.64

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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.