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Finding the Fourth Proportional to 93.90, 129.60 and 78.35

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Solution

The fourth proportional to 93.90, 129.60 and 78.35 is: 108.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.90 : 129.60 = 78.35 : x
  2. Step 2: Convert to fraction form
    93.90/129.60 = 78.35/x
  3. Step 3: Cross multiply
    93.90x = 129.60 × 78.35
  4. Step 4: Simplify right side
    93.90x = 10,153.51
  5. Step 5: Solve for x
    x = 10,153.51/93.90
  6. Step 6: Final answer
    x = 108.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.