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Finding the Fourth Proportional to 878.76, 1,315.40 and 647.91

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Solution

The fourth proportional to 878.76, 1,315.40 and 647.91 is: 969.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.76 : 1,315.40 = 647.91 : x
  2. Step 2: Convert to fraction form
    878.76/1,315.40 = 647.91/x
  3. Step 3: Cross multiply
    878.76x = 1,315.40 × 647.91
  4. Step 4: Simplify right side
    878.76x = 852,257.57
  5. Step 5: Solve for x
    x = 852,257.57/878.76
  6. Step 6: Final answer
    x = 969.84

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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.