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Finding the Fourth Proportional to 405.90, 555.18 and 399.52

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Solution

The fourth proportional to 405.90, 555.18 and 399.52 is: 546.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.90 : 555.18 = 399.52 : x
  2. Step 2: Convert to fraction form
    405.90/555.18 = 399.52/x
  3. Step 3: Cross multiply
    405.90x = 555.18 × 399.52
  4. Step 4: Simplify right side
    405.90x = 221,804.71
  5. Step 5: Solve for x
    x = 221,804.71/405.90
  6. Step 6: Final answer
    x = 546.45

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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.