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Finding the Fourth Proportional to 215.15, 322.88 and 86.90

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Solution

The fourth proportional to 215.15, 322.88 and 86.90 is: 130.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.15 : 322.88 = 86.90 : x
  2. Step 2: Convert to fraction form
    215.15/322.88 = 86.90/x
  3. Step 3: Cross multiply
    215.15x = 322.88 × 86.90
  4. Step 4: Simplify right side
    215.15x = 28,056.22
  5. Step 5: Solve for x
    x = 28,056.22/215.15
  6. Step 6: Final answer
    x = 130.41

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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.