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Finding the Fourth Proportional to 430.32, 641.91 and 389.28

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Solution

The fourth proportional to 430.32, 641.91 and 389.28 is: 580.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.32 : 641.91 = 389.28 : x
  2. Step 2: Convert to fraction form
    430.32/641.91 = 389.28/x
  3. Step 3: Cross multiply
    430.32x = 641.91 × 389.28
  4. Step 4: Simplify right side
    430.32x = 249,882.72
  5. Step 5: Solve for x
    x = 249,882.72/430.32
  6. Step 6: Final answer
    x = 580.69

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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.