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Finding the Fourth Proportional to 865.40, 1,298.09 and 378.32

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Solution

The fourth proportional to 865.40, 1,298.09 and 378.32 is: 567.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.40 : 1,298.09 = 378.32 : x
  2. Step 2: Convert to fraction form
    865.40/1,298.09 = 378.32/x
  3. Step 3: Cross multiply
    865.40x = 1,298.09 × 378.32
  4. Step 4: Simplify right side
    865.40x = 491,087.86
  5. Step 5: Solve for x
    x = 491,087.86/865.40
  6. Step 6: Final answer
    x = 567.47

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Double scale
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1.5x scale

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.