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Finding the Fourth Proportional to 210.65, 315.85 and 87.28

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Solution

The fourth proportional to 210.65, 315.85 and 87.28 is: 130.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.65 : 315.85 = 87.28 : x
  2. Step 2: Convert to fraction form
    210.65/315.85 = 87.28/x
  3. Step 3: Cross multiply
    210.65x = 315.85 × 87.28
  4. Step 4: Simplify right side
    210.65x = 27,566.54
  5. Step 5: Solve for x
    x = 27,566.54/210.65
  6. Step 6: Final answer
    x = 130.86

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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.