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Finding the Fourth Proportional to 784.64, 1,177.12 and 647.84

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Solution

The fourth proportional to 784.64, 1,177.12 and 647.84 is: 971.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.64 : 1,177.12 = 647.84 : x
  2. Step 2: Convert to fraction form
    784.64/1,177.12 = 647.84/x
  3. Step 3: Cross multiply
    784.64x = 1,177.12 × 647.84
  4. Step 4: Simplify right side
    784.64x = 762,585.42
  5. Step 5: Solve for x
    x = 762,585.42/784.64
  6. Step 6: Final answer
    x = 971.89

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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.