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Finding the Fourth Proportional to 102.90, 153.70 and 77.08

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Solution

The fourth proportional to 102.90, 153.70 and 77.08 is: 115.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.90 : 153.70 = 77.08 : x
  2. Step 2: Convert to fraction form
    102.90/153.70 = 77.08/x
  3. Step 3: Cross multiply
    102.90x = 153.70 × 77.08
  4. Step 4: Simplify right side
    102.90x = 11,847.20
  5. Step 5: Solve for x
    x = 11,847.20/102.90
  6. Step 6: Final answer
    x = 115.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.