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Finding the Fourth Proportional to 691.28, 1,036.90 and 171.28

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Solution

The fourth proportional to 691.28, 1,036.90 and 171.28 is: 256.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.28 : 1,036.90 = 171.28 : x
  2. Step 2: Convert to fraction form
    691.28/1,036.90 = 171.28/x
  3. Step 3: Cross multiply
    691.28x = 1,036.90 × 171.28
  4. Step 4: Simplify right side
    691.28x = 177,598.87
  5. Step 5: Solve for x
    x = 177,598.87/691.28
  6. Step 6: Final answer
    x = 256.91

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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.