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Finding the Fourth Proportional to 102.15, 153.21 and 87.57

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Solution

The fourth proportional to 102.15, 153.21 and 87.57 is: 131.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.15 : 153.21 = 87.57 : x
  2. Step 2: Convert to fraction form
    102.15/153.21 = 87.57/x
  3. Step 3: Cross multiply
    102.15x = 153.21 × 87.57
  4. Step 4: Simplify right side
    102.15x = 13,416.60
  5. Step 5: Solve for x
    x = 13,416.60/102.15
  6. Step 6: Final answer
    x = 131.34

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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.