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Finding the Fourth Proportional to 691.12, 1,036.42 and 280.15

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Solution

The fourth proportional to 691.12, 1,036.42 and 280.15 is: 420.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.12 : 1,036.42 = 280.15 : x
  2. Step 2: Convert to fraction form
    691.12/1,036.42 = 280.15/x
  3. Step 3: Cross multiply
    691.12x = 1,036.42 × 280.15
  4. Step 4: Simplify right side
    691.12x = 290,353.06
  5. Step 5: Solve for x
    x = 290,353.06/691.12
  6. Step 6: Final answer
    x = 420.12

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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.