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Finding the Fourth Proportional to 405, 554.84 and 390.42

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Solution

The fourth proportional to 405, 554.84 and 390.42 is: 534.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    405 : 554.84 = 390.42 : x
  2. Step 2: Convert to fraction form
    405/554.84 = 390.42/x
  3. Step 3: Cross multiply
    405x = 554.84 × 390.42
  4. Step 4: Simplify right side
    405x = 216,620.63
  5. Step 5: Solve for x
    x = 216,620.63/405
  6. Step 6: Final answer
    x = 534.87

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.