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Finding the Fourth Proportional to 405.12, 555.66 and 386.64

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Solution

The fourth proportional to 405.12, 555.66 and 386.64 is: 530.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.12 : 555.66 = 386.64 : x
  2. Step 2: Convert to fraction form
    405.12/555.66 = 386.64/x
  3. Step 3: Cross multiply
    405.12x = 555.66 × 386.64
  4. Step 4: Simplify right side
    405.12x = 214,840.38
  5. Step 5: Solve for x
    x = 214,840.38/405.12
  6. Step 6: Final answer
    x = 530.31

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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.