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Finding the Fourth Proportional to 878.81, 1,212.71 and 505.80

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Solution

The fourth proportional to 878.81, 1,212.71 and 505.80 is: 697.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.81 : 1,212.71 = 505.80 : x
  2. Step 2: Convert to fraction form
    878.81/1,212.71 = 505.80/x
  3. Step 3: Cross multiply
    878.81x = 1,212.71 × 505.80
  4. Step 4: Simplify right side
    878.81x = 613,386.19
  5. Step 5: Solve for x
    x = 613,386.19/878.81
  6. Step 6: Final answer
    x = 697.98

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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.