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Finding the Fourth Proportional to 991.32, 1,369.08 and 711.78

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Solution

The fourth proportional to 991.32, 1,369.08 and 711.78 is: 983.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.32 : 1,369.08 = 711.78 : x
  2. Step 2: Convert to fraction form
    991.32/1,369.08 = 711.78/x
  3. Step 3: Cross multiply
    991.32x = 1,369.08 × 711.78
  4. Step 4: Simplify right side
    991.32x = 974,483.76
  5. Step 5: Solve for x
    x = 974,483.76/991.32
  6. Step 6: Final answer
    x = 983.02

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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.