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Finding the Fourth Proportional to 687.49, 948.71 and 392.85

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Solution

The fourth proportional to 687.49, 948.71 and 392.85 is: 542.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.49 : 948.71 = 392.85 : x
  2. Step 2: Convert to fraction form
    687.49/948.71 = 392.85/x
  3. Step 3: Cross multiply
    687.49x = 948.71 × 392.85
  4. Step 4: Simplify right side
    687.49x = 372,701.71
  5. Step 5: Solve for x
    x = 372,701.71/687.49
  6. Step 6: Final answer
    x = 542.12

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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.