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Finding the Fourth Proportional to 862.10, 1,291.80 and 724.40

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Solution

The fourth proportional to 862.10, 1,291.80 and 724.40 is: 1,085.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.10 : 1,291.80 = 724.40 : x
  2. Step 2: Convert to fraction form
    862.10/1,291.80 = 724.40/x
  3. Step 3: Cross multiply
    862.10x = 1,291.80 × 724.40
  4. Step 4: Simplify right side
    862.10x = 935,779.92
  5. Step 5: Solve for x
    x = 935,779.92/862.10
  6. Step 6: Final answer
    x = 1,085.47

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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.