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Finding the Fourth Proportional to 93.78, 129.51 and 64.80

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Solution

The fourth proportional to 93.78, 129.51 and 64.80 is: 89.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 129.51 = 64.80 : x
  2. Step 2: Convert to fraction form
    93.78/129.51 = 64.80/x
  3. Step 3: Cross multiply
    93.78x = 129.51 × 64.80
  4. Step 4: Simplify right side
    93.78x = 8,392.25
  5. Step 5: Solve for x
    x = 8,392.25/93.78
  6. Step 6: Final answer
    x = 89.49

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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.