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Finding the Fourth Proportional to 821, 1,221.85 and 802.76

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Solution

The fourth proportional to 821, 1,221.85 and 802.76 is: 1,194.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    821 : 1,221.85 = 802.76 : x
  2. Step 2: Convert to fraction form
    821/1,221.85 = 802.76/x
  3. Step 3: Cross multiply
    821x = 1,221.85 × 802.76
  4. Step 4: Simplify right side
    821x = 980,852.31
  5. Step 5: Solve for x
    x = 980,852.31/821
  6. Step 6: Final answer
    x = 1,194.70

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.