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Finding the Fourth Proportional to 687.65, 948.79 and 392.76

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Solution

The fourth proportional to 687.65, 948.79 and 392.76 is: 541.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.65 : 948.79 = 392.76 : x
  2. Step 2: Convert to fraction form
    687.65/948.79 = 392.76/x
  3. Step 3: Cross multiply
    687.65x = 948.79 × 392.76
  4. Step 4: Simplify right side
    687.65x = 372,646.76
  5. Step 5: Solve for x
    x = 372,646.76/687.65
  6. Step 6: Final answer
    x = 541.91

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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.