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Finding the Fourth Proportional to 878.49, 1,317.12 and 391.28

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Solution

The fourth proportional to 878.49, 1,317.12 and 391.28 is: 586.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.49 : 1,317.12 = 391.28 : x
  2. Step 2: Convert to fraction form
    878.49/1,317.12 = 391.28/x
  3. Step 3: Cross multiply
    878.49x = 1,317.12 × 391.28
  4. Step 4: Simplify right side
    878.49x = 515,356.13
  5. Step 5: Solve for x
    x = 515,356.13/878.49
  6. Step 6: Final answer
    x = 586.64

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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.