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Finding the Fourth Proportional to 687.12, 948.22 and 392.39

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Solution

The fourth proportional to 687.12, 948.22 and 392.39 is: 541.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.12 : 948.22 = 392.39 : x
  2. Step 2: Convert to fraction form
    687.12/948.22 = 392.39/x
  3. Step 3: Cross multiply
    687.12x = 948.22 × 392.39
  4. Step 4: Simplify right side
    687.12x = 372,065.34
  5. Step 5: Solve for x
    x = 372,065.34/687.12
  6. Step 6: Final answer
    x = 541.49

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.