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Finding the Fourth Proportional to 802.40, 1,203.60 and 687.20

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Solution

The fourth proportional to 802.40, 1,203.60 and 687.20 is: 1,030.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    802.40 : 1,203.60 = 687.20 : x
  2. Step 2: Convert to fraction form
    802.40/1,203.60 = 687.20/x
  3. Step 3: Cross multiply
    802.40x = 1,203.60 × 687.20
  4. Step 4: Simplify right side
    802.40x = 827,113.92
  5. Step 5: Solve for x
    x = 827,113.92/802.40
  6. Step 6: Final answer
    x = 1,030.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.