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Finding the Fourth Proportional to 689.12, 1,033.42 and 278.15

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Solution

The fourth proportional to 689.12, 1,033.42 and 278.15 is: 417.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.12 : 1,033.42 = 278.15 : x
  2. Step 2: Convert to fraction form
    689.12/1,033.42 = 278.15/x
  3. Step 3: Cross multiply
    689.12x = 1,033.42 × 278.15
  4. Step 4: Simplify right side
    689.12x = 287,445.77
  5. Step 5: Solve for x
    x = 287,445.77/689.12
  6. Step 6: Final answer
    x = 417.12

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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.