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Finding the Fourth Proportional to 918.50, 1,267.65 and 638.58

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Solution

The fourth proportional to 918.50, 1,267.65 and 638.58 is: 881.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.50 : 1,267.65 = 638.58 : x
  2. Step 2: Convert to fraction form
    918.50/1,267.65 = 638.58/x
  3. Step 3: Cross multiply
    918.50x = 1,267.65 × 638.58
  4. Step 4: Simplify right side
    918.50x = 809,495.94
  5. Step 5: Solve for x
    x = 809,495.94/918.50
  6. Step 6: Final answer
    x = 881.32

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.