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Finding the Fourth Proportional to 687.12, 942.55 and 681.28

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Solution

The fourth proportional to 687.12, 942.55 and 681.28 is: 934.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.12 : 942.55 = 681.28 : x
  2. Step 2: Convert to fraction form
    687.12/942.55 = 681.28/x
  3. Step 3: Cross multiply
    687.12x = 942.55 × 681.28
  4. Step 4: Simplify right side
    687.12x = 642,140.46
  5. Step 5: Solve for x
    x = 642,140.46/687.12
  6. Step 6: Final answer
    x = 934.54

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.