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Finding the Fourth Proportional to 430.40, 647.94 and 385.75

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Solution

The fourth proportional to 430.40, 647.94 and 385.75 is: 580.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.40 : 647.94 = 385.75 : x
  2. Step 2: Convert to fraction form
    430.40/647.94 = 385.75/x
  3. Step 3: Cross multiply
    430.40x = 647.94 × 385.75
  4. Step 4: Simplify right side
    430.40x = 249,942.86
  5. Step 5: Solve for x
    x = 249,942.86/430.40
  6. Step 6: Final answer
    x = 580.72

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.