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Finding the Fourth Proportional to 288.40, 430.38 and 257.64

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Solution

The fourth proportional to 288.40, 430.38 and 257.64 is: 384.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.40 : 430.38 = 257.64 : x
  2. Step 2: Convert to fraction form
    288.40/430.38 = 257.64/x
  3. Step 3: Cross multiply
    288.40x = 430.38 × 257.64
  4. Step 4: Simplify right side
    288.40x = 110,883.10
  5. Step 5: Solve for x
    x = 110,883.10/288.40
  6. Step 6: Final answer
    x = 384.48

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.