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Finding the Fourth Proportional to 102.15, 152.64 and 90.72

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Solution

The fourth proportional to 102.15, 152.64 and 90.72 is: 135.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.15 : 152.64 = 90.72 : x
  2. Step 2: Convert to fraction form
    102.15/152.64 = 90.72/x
  3. Step 3: Cross multiply
    102.15x = 152.64 × 90.72
  4. Step 4: Simplify right side
    102.15x = 13,847.50
  5. Step 5: Solve for x
    x = 13,847.50/102.15
  6. Step 6: Final answer
    x = 135.56

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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.