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Finding the Fourth Proportional to 691.56, 1,036.49 and 399.20

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Solution

The fourth proportional to 691.56, 1,036.49 and 399.20 is: 598.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.56 : 1,036.49 = 399.20 : x
  2. Step 2: Convert to fraction form
    691.56/1,036.49 = 399.20/x
  3. Step 3: Cross multiply
    691.56x = 1,036.49 × 399.20
  4. Step 4: Simplify right side
    691.56x = 413,759.63
  5. Step 5: Solve for x
    x = 413,759.63/691.56
  6. Step 6: Final answer
    x = 598.30

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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.