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Finding the Fourth Proportional to 1,140.49, 1,573.80 and 643.15

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Solution

The fourth proportional to 1,140.49, 1,573.80 and 643.15 is: 887.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,140.49 : 1,573.80 = 643.15 : x
  2. Step 2: Convert to fraction form
    1,140.49/1,573.80 = 643.15/x
  3. Step 3: Cross multiply
    1,140.49x = 1,573.80 × 643.15
  4. Step 4: Simplify right side
    1,140.49x = 1,012,189.47
  5. Step 5: Solve for x
    x = 1,012,189.47/1,140.49
  6. Step 6: Final answer
    x = 887.50

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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.