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Finding the Fourth Proportional to 691.45, 1,036.29 and 280.35

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Solution

The fourth proportional to 691.45, 1,036.29 and 280.35 is: 420.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.45 : 1,036.29 = 280.35 : x
  2. Step 2: Convert to fraction form
    691.45/1,036.29 = 280.35/x
  3. Step 3: Cross multiply
    691.45x = 1,036.29 × 280.35
  4. Step 4: Simplify right side
    691.45x = 290,524.95
  5. Step 5: Solve for x
    x = 290,524.95/691.45
  6. Step 6: Final answer
    x = 420.17

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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.