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Finding the Fourth Proportional to 210.69, 315.84 and 85.53

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Solution

The fourth proportional to 210.69, 315.84 and 85.53 is: 128.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.69 : 315.84 = 85.53 : x
  2. Step 2: Convert to fraction form
    210.69/315.84 = 85.53/x
  3. Step 3: Cross multiply
    210.69x = 315.84 × 85.53
  4. Step 4: Simplify right side
    210.69x = 27,013.80
  5. Step 5: Solve for x
    x = 27,013.80/210.69
  6. Step 6: Final answer
    x = 128.22

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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.