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Finding the Fourth Proportional to 947.40, 1,422.12 and 686.28

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Solution

The fourth proportional to 947.40, 1,422.12 and 686.28 is: 1,030.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.40 : 1,422.12 = 686.28 : x
  2. Step 2: Convert to fraction form
    947.40/1,422.12 = 686.28/x
  3. Step 3: Cross multiply
    947.40x = 1,422.12 × 686.28
  4. Step 4: Simplify right side
    947.40x = 975,972.51
  5. Step 5: Solve for x
    x = 975,972.51/947.40
  6. Step 6: Final answer
    x = 1,030.16

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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.