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Finding the Fourth Proportional to 748.68, 1,128.45 and 687.12

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Solution

The fourth proportional to 748.68, 1,128.45 and 687.12 is: 1,035.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    748.68 : 1,128.45 = 687.12 : x
  2. Step 2: Convert to fraction form
    748.68/1,128.45 = 687.12/x
  3. Step 3: Cross multiply
    748.68x = 1,128.45 × 687.12
  4. Step 4: Simplify right side
    748.68x = 775,380.56
  5. Step 5: Solve for x
    x = 775,380.56/748.68
  6. Step 6: Final answer
    x = 1,035.66

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.