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Finding the Fourth Proportional to 878.02, 1,211.58 and 499.90

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Solution

The fourth proportional to 878.02, 1,211.58 and 499.90 is: 689.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.02 : 1,211.58 = 499.90 : x
  2. Step 2: Convert to fraction form
    878.02/1,211.58 = 499.90/x
  3. Step 3: Cross multiply
    878.02x = 1,211.58 × 499.90
  4. Step 4: Simplify right side
    878.02x = 605,668.84
  5. Step 5: Solve for x
    x = 605,668.84/878.02
  6. Step 6: Final answer
    x = 689.81

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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.