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Finding the Fourth Proportional to 670.78, 1,005.36 and 285.22

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Solution

The fourth proportional to 670.78, 1,005.36 and 285.22 is: 427.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.78 : 1,005.36 = 285.22 : x
  2. Step 2: Convert to fraction form
    670.78/1,005.36 = 285.22/x
  3. Step 3: Cross multiply
    670.78x = 1,005.36 × 285.22
  4. Step 4: Simplify right side
    670.78x = 286,747.35
  5. Step 5: Solve for x
    x = 286,747.35/670.78
  6. Step 6: Final answer
    x = 427.48

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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.