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Finding the Fourth Proportional to 979.92, 1,353.60 and 686.16

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Solution

The fourth proportional to 979.92, 1,353.60 and 686.16 is: 947.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.92 : 1,353.60 = 686.16 : x
  2. Step 2: Convert to fraction form
    979.92/1,353.60 = 686.16/x
  3. Step 3: Cross multiply
    979.92x = 1,353.60 × 686.16
  4. Step 4: Simplify right side
    979.92x = 928,786.18
  5. Step 5: Solve for x
    x = 928,786.18/979.92
  6. Step 6: Final answer
    x = 947.82

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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.