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Finding the Fourth Proportional to 210.15, 314.61 and 128.76

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Solution

The fourth proportional to 210.15, 314.61 and 128.76 is: 192.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.15 : 314.61 = 128.76 : x
  2. Step 2: Convert to fraction form
    210.15/314.61 = 128.76/x
  3. Step 3: Cross multiply
    210.15x = 314.61 × 128.76
  4. Step 4: Simplify right side
    210.15x = 40,509.18
  5. Step 5: Solve for x
    x = 40,509.18/210.15
  6. Step 6: Final answer
    x = 192.76

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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.