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Finding the Fourth Proportional to 1,247.31, 1,871.24 and 785.70

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Solution

The fourth proportional to 1,247.31, 1,871.24 and 785.70 is: 1,178.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.31 : 1,871.24 = 785.70 : x
  2. Step 2: Convert to fraction form
    1,247.31/1,871.24 = 785.70/x
  3. Step 3: Cross multiply
    1,247.31x = 1,871.24 × 785.70
  4. Step 4: Simplify right side
    1,247.31x = 1,470,229.34
  5. Step 5: Solve for x
    x = 1,470,229.34/1,247.31
  6. Step 6: Final answer
    x = 1,178.72

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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.