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Finding the Fourth Proportional to 215.65, 297.57 and 128.35

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Solution

The fourth proportional to 215.65, 297.57 and 128.35 is: 177.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.65 : 297.57 = 128.35 : x
  2. Step 2: Convert to fraction form
    215.65/297.57 = 128.35/x
  3. Step 3: Cross multiply
    215.65x = 297.57 × 128.35
  4. Step 4: Simplify right side
    215.65x = 38,193.11
  5. Step 5: Solve for x
    x = 38,193.11/215.65
  6. Step 6: Final answer
    x = 177.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.