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Finding the Fourth Proportional to 686.72, 1,024.24 and 643.52

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Solution

The fourth proportional to 686.72, 1,024.24 and 643.52 is: 959.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.72 : 1,024.24 = 643.52 : x
  2. Step 2: Convert to fraction form
    686.72/1,024.24 = 643.52/x
  3. Step 3: Cross multiply
    686.72x = 1,024.24 × 643.52
  4. Step 4: Simplify right side
    686.72x = 659,118.92
  5. Step 5: Solve for x
    x = 659,118.92/686.72
  6. Step 6: Final answer
    x = 959.81

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1.5x scale

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.