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Finding the Fourth Proportional to 878.60, 1,317.90 and 858.35

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Solution

The fourth proportional to 878.60, 1,317.90 and 858.35 is: 1,287.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.60 : 1,317.90 = 858.35 : x
  2. Step 2: Convert to fraction form
    878.60/1,317.90 = 858.35/x
  3. Step 3: Cross multiply
    878.60x = 1,317.90 × 858.35
  4. Step 4: Simplify right side
    878.60x = 1,131,219.47
  5. Step 5: Solve for x
    x = 1,131,219.47/878.60
  6. Step 6: Final answer
    x = 1,287.53

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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.