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Finding the Fourth Proportional to 1,140.70, 1,574.04 and 643.30

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Solution

The fourth proportional to 1,140.70, 1,574.04 and 643.30 is: 887.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,140.70 : 1,574.04 = 643.30 : x
  2. Step 2: Convert to fraction form
    1,140.70/1,574.04 = 643.30/x
  3. Step 3: Cross multiply
    1,140.70x = 1,574.04 × 643.30
  4. Step 4: Simplify right side
    1,140.70x = 1,012,579.93
  5. Step 5: Solve for x
    x = 1,012,579.93/1,140.70
  6. Step 6: Final answer
    x = 887.68

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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.