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Finding the Fourth Proportional to 691.16, 1,036.80 and 280.52

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Solution

The fourth proportional to 691.16, 1,036.80 and 280.52 is: 420.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.16 : 1,036.80 = 280.52 : x
  2. Step 2: Convert to fraction form
    691.16/1,036.80 = 280.52/x
  3. Step 3: Cross multiply
    691.16x = 1,036.80 × 280.52
  4. Step 4: Simplify right side
    691.16x = 290,843.14
  5. Step 5: Solve for x
    x = 290,843.14/691.16
  6. Step 6: Final answer
    x = 420.80

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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.