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Finding the Fourth Proportional to 874.72, 1,312.68 and 644.20

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Solution

The fourth proportional to 874.72, 1,312.68 and 644.20 is: 966.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.72 : 1,312.68 = 644.20 : x
  2. Step 2: Convert to fraction form
    874.72/1,312.68 = 644.20/x
  3. Step 3: Cross multiply
    874.72x = 1,312.68 × 644.20
  4. Step 4: Simplify right side
    874.72x = 845,628.46
  5. Step 5: Solve for x
    x = 845,628.46/874.72
  6. Step 6: Final answer
    x = 966.74

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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.