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Finding the Fourth Proportional to 287.40, 430.56 and 218.70

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Solution

The fourth proportional to 287.40, 430.56 and 218.70 is: 327.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.40 : 430.56 = 218.70 : x
  2. Step 2: Convert to fraction form
    287.40/430.56 = 218.70/x
  3. Step 3: Cross multiply
    287.40x = 430.56 × 218.70
  4. Step 4: Simplify right side
    287.40x = 94,163.47
  5. Step 5: Solve for x
    x = 94,163.47/287.40
  6. Step 6: Final answer
    x = 327.64

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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.