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Finding the Fourth Proportional to 1,128.63, 1,557.51 and 686.45

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Solution

The fourth proportional to 1,128.63, 1,557.51 and 686.45 is: 947.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.63 : 1,557.51 = 686.45 : x
  2. Step 2: Convert to fraction form
    1,128.63/1,557.51 = 686.45/x
  3. Step 3: Cross multiply
    1,128.63x = 1,557.51 × 686.45
  4. Step 4: Simplify right side
    1,128.63x = 1,069,152.74
  5. Step 5: Solve for x
    x = 1,069,152.74/1,128.63
  6. Step 6: Final answer
    x = 947.30

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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.