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Finding the Fourth Proportional to 678.36, 1,015.08 and 561.72

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Solution

The fourth proportional to 678.36, 1,015.08 and 561.72 is: 840.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.36 : 1,015.08 = 561.72 : x
  2. Step 2: Convert to fraction form
    678.36/1,015.08 = 561.72/x
  3. Step 3: Cross multiply
    678.36x = 1,015.08 × 561.72
  4. Step 4: Simplify right side
    678.36x = 570,190.74
  5. Step 5: Solve for x
    x = 570,190.74/678.36
  6. Step 6: Final answer
    x = 840.54

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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.