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Finding the Fourth Proportional to 647.76, 971.12 and 257.72

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Solution

The fourth proportional to 647.76, 971.12 and 257.72 is: 386.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.76 : 971.12 = 257.72 : x
  2. Step 2: Convert to fraction form
    647.76/971.12 = 257.72/x
  3. Step 3: Cross multiply
    647.76x = 971.12 × 257.72
  4. Step 4: Simplify right side
    647.76x = 250,272.84
  5. Step 5: Solve for x
    x = 250,272.84/647.76
  6. Step 6: Final answer
    x = 386.36

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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.