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Finding the Fourth Proportional to 661.68, 991.37 and 430.29

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Solution

The fourth proportional to 661.68, 991.37 and 430.29 is: 644.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.68 : 991.37 = 430.29 : x
  2. Step 2: Convert to fraction form
    661.68/991.37 = 430.29/x
  3. Step 3: Cross multiply
    661.68x = 991.37 × 430.29
  4. Step 4: Simplify right side
    661.68x = 426,574.45
  5. Step 5: Solve for x
    x = 426,574.45/661.68
  6. Step 6: Final answer
    x = 644.68

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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.