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Finding the Fourth Proportional to 102.64, 153.94 and 86.40

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Solution

The fourth proportional to 102.64, 153.94 and 86.40 is: 129.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.64 : 153.94 = 86.40 : x
  2. Step 2: Convert to fraction form
    102.64/153.94 = 86.40/x
  3. Step 3: Cross multiply
    102.64x = 153.94 × 86.40
  4. Step 4: Simplify right side
    102.64x = 13,300.42
  5. Step 5: Solve for x
    x = 13,300.42/102.64
  6. Step 6: Final answer
    x = 129.58

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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.