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Finding the Fourth Proportional to 669.76, 1,005.12 and 285.12

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Solution

The fourth proportional to 669.76, 1,005.12 and 285.12 is: 427.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.76 : 1,005.12 = 285.12 : x
  2. Step 2: Convert to fraction form
    669.76/1,005.12 = 285.12/x
  3. Step 3: Cross multiply
    669.76x = 1,005.12 × 285.12
  4. Step 4: Simplify right side
    669.76x = 286,579.81
  5. Step 5: Solve for x
    x = 286,579.81/669.76
  6. Step 6: Final answer
    x = 427.88

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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.