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Finding the Fourth Proportional to 870.91, 1,306.40 and 221.65

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Solution

The fourth proportional to 870.91, 1,306.40 and 221.65 is: 332.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.91 : 1,306.40 = 221.65 : x
  2. Step 2: Convert to fraction form
    870.91/1,306.40 = 221.65/x
  3. Step 3: Cross multiply
    870.91x = 1,306.40 × 221.65
  4. Step 4: Simplify right side
    870.91x = 289,563.56
  5. Step 5: Solve for x
    x = 289,563.56/870.91
  6. Step 6: Final answer
    x = 332.48

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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.