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Finding the Fourth Proportional to 980.76, 1,353.51 and 686.12

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Solution

The fourth proportional to 980.76, 1,353.51 and 686.12 is: 946.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.76 : 1,353.51 = 686.12 : x
  2. Step 2: Convert to fraction form
    980.76/1,353.51 = 686.12/x
  3. Step 3: Cross multiply
    980.76x = 1,353.51 × 686.12
  4. Step 4: Simplify right side
    980.76x = 928,671.13
  5. Step 5: Solve for x
    x = 928,671.13/980.76
  6. Step 6: Final answer
    x = 946.89

Related Problems

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Half scale
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Double scale
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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.