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Finding the Fourth Proportional to 728.68, 1,089.96 and 638.68

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Solution

The fourth proportional to 728.68, 1,089.96 and 638.68 is: 955.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.68 : 1,089.96 = 638.68 : x
  2. Step 2: Convert to fraction form
    728.68/1,089.96 = 638.68/x
  3. Step 3: Cross multiply
    728.68x = 1,089.96 × 638.68
  4. Step 4: Simplify right side
    728.68x = 696,135.65
  5. Step 5: Solve for x
    x = 696,135.65/728.68
  6. Step 6: Final answer
    x = 955.34

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1.5x scale

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.