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Finding the Fourth Proportional to 405.64, 607.86 and 213

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Solution

The fourth proportional to 405.64, 607.86 and 213 is: 319.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.64 : 607.86 = 213 : x
  2. Step 2: Convert to fraction form
    405.64/607.86 = 213/x
  3. Step 3: Cross multiply
    405.64x = 607.86 × 213
  4. Step 4: Simplify right side
    405.64x = 129,474.18
  5. Step 5: Solve for x
    x = 129,474.18/405.64
  6. Step 6: Final answer
    x = 319.18

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.