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Finding the Fourth Proportional to 1,128.16, 1,557.16 and 686.20

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Solution

The fourth proportional to 1,128.16, 1,557.16 and 686.20 is: 947.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.16 : 1,557.16 = 686.20 : x
  2. Step 2: Convert to fraction form
    1,128.16/1,557.16 = 686.20/x
  3. Step 3: Cross multiply
    1,128.16x = 1,557.16 × 686.20
  4. Step 4: Simplify right side
    1,128.16x = 1,068,519.76
  5. Step 5: Solve for x
    x = 1,068,519.76/1,128.16
  6. Step 6: Final answer
    x = 947.14

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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.