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Finding the Fourth Proportional to 684.72, 1,021.32 and 639.36

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Solution

The fourth proportional to 684.72, 1,021.32 and 639.36 is: 953.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.72 : 1,021.32 = 639.36 : x
  2. Step 2: Convert to fraction form
    684.72/1,021.32 = 639.36/x
  3. Step 3: Cross multiply
    684.72x = 1,021.32 × 639.36
  4. Step 4: Simplify right side
    684.72x = 652,991.16
  5. Step 5: Solve for x
    x = 652,991.16/684.72
  6. Step 6: Final answer
    x = 953.66

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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.