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Finding the Fourth Proportional to 678.72, 1,019.70 and 487.56

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Solution

The fourth proportional to 678.72, 1,019.70 and 487.56 is: 732.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.72 : 1,019.70 = 487.56 : x
  2. Step 2: Convert to fraction form
    678.72/1,019.70 = 487.56/x
  3. Step 3: Cross multiply
    678.72x = 1,019.70 × 487.56
  4. Step 4: Simplify right side
    678.72x = 497,164.93
  5. Step 5: Solve for x
    x = 497,164.93/678.72
  6. Step 6: Final answer
    x = 732.50

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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.