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Finding the Fourth Proportional to 643.10, 891.20 and 630.77

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Solution

The fourth proportional to 643.10, 891.20 and 630.77 is: 874.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.10 : 891.20 = 630.77 : x
  2. Step 2: Convert to fraction form
    643.10/891.20 = 630.77/x
  3. Step 3: Cross multiply
    643.10x = 891.20 × 630.77
  4. Step 4: Simplify right side
    643.10x = 562,134.61
  5. Step 5: Solve for x
    x = 562,134.61/643.10
  6. Step 6: Final answer
    x = 874.11

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.