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Finding the Fourth Proportional to 478.77, 660.42 and 390.35

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Solution

The fourth proportional to 478.77, 660.42 and 390.35 is: 538.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.77 : 660.42 = 390.35 : x
  2. Step 2: Convert to fraction form
    478.77/660.42 = 390.35/x
  3. Step 3: Cross multiply
    478.77x = 660.42 × 390.35
  4. Step 4: Simplify right side
    478.77x = 257,791.64
  5. Step 5: Solve for x
    x = 257,791.64/478.77
  6. Step 6: Final answer
    x = 538.45

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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.