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Finding the Fourth Proportional to 985.78, 1,478.71 and 327.72

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Solution

The fourth proportional to 985.78, 1,478.71 and 327.72 is: 491.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.78 : 1,478.71 = 327.72 : x
  2. Step 2: Convert to fraction form
    985.78/1,478.71 = 327.72/x
  3. Step 3: Cross multiply
    985.78x = 1,478.71 × 327.72
  4. Step 4: Simplify right side
    985.78x = 484,601.40
  5. Step 5: Solve for x
    x = 484,601.40/985.78
  6. Step 6: Final answer
    x = 491.59

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.