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Finding the Fourth Proportional to 1,230.50, 1,698.35 and 811.53

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Solution

The fourth proportional to 1,230.50, 1,698.35 and 811.53 is: 1,120.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,230.50 : 1,698.35 = 811.53 : x
  2. Step 2: Convert to fraction form
    1,230.50/1,698.35 = 811.53/x
  3. Step 3: Cross multiply
    1,230.50x = 1,698.35 × 811.53
  4. Step 4: Simplify right side
    1,230.50x = 1,378,261.98
  5. Step 5: Solve for x
    x = 1,378,261.98/1,230.50
  6. Step 6: Final answer
    x = 1,120.08

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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.