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Finding the Fourth Proportional to 661.79, 991.58 and 430.34

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Solution

The fourth proportional to 661.79, 991.58 and 430.34 is: 644.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.79 : 991.58 = 430.34 : x
  2. Step 2: Convert to fraction form
    661.79/991.58 = 430.34/x
  3. Step 3: Cross multiply
    661.79x = 991.58 × 430.34
  4. Step 4: Simplify right side
    661.79x = 426,709.43
  5. Step 5: Solve for x
    x = 426,709.43/661.79
  6. Step 6: Final answer
    x = 644.78

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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.