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Finding the Fourth Proportional to 102.51, 153.89 and 85.60

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Solution

The fourth proportional to 102.51, 153.89 and 85.60 is: 128.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.51 : 153.89 = 85.60 : x
  2. Step 2: Convert to fraction form
    102.51/153.89 = 85.60/x
  3. Step 3: Cross multiply
    102.51x = 153.89 × 85.60
  4. Step 4: Simplify right side
    102.51x = 13,172.98
  5. Step 5: Solve for x
    x = 13,172.98/102.51
  6. Step 6: Final answer
    x = 128.50

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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.