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Finding the Fourth Proportional to 1,128.79, 1,557.79 and 631.47

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Solution

The fourth proportional to 1,128.79, 1,557.79 and 631.47 is: 871.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.79 : 1,557.79 = 631.47 : x
  2. Step 2: Convert to fraction form
    1,128.79/1,557.79 = 631.47/x
  3. Step 3: Cross multiply
    1,128.79x = 1,557.79 × 631.47
  4. Step 4: Simplify right side
    1,128.79x = 983,703.69
  5. Step 5: Solve for x
    x = 983,703.69/1,128.79
  6. Step 6: Final answer
    x = 871.47

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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.