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Finding the Fourth Proportional to 691.21, 1,036.82 and 280.59

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Solution

The fourth proportional to 691.21, 1,036.82 and 280.59 is: 420.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.21 : 1,036.82 = 280.59 : x
  2. Step 2: Convert to fraction form
    691.21/1,036.82 = 280.59/x
  3. Step 3: Cross multiply
    691.21x = 1,036.82 × 280.59
  4. Step 4: Simplify right side
    691.21x = 290,921.32
  5. Step 5: Solve for x
    x = 290,921.32/691.21
  6. Step 6: Final answer
    x = 420.89

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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.