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Finding the Fourth Proportional to 690.55, 1,035.80 and 279.68

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Solution

The fourth proportional to 690.55, 1,035.80 and 279.68 is: 419.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.55 : 1,035.80 = 279.68 : x
  2. Step 2: Convert to fraction form
    690.55/1,035.80 = 279.68/x
  3. Step 3: Cross multiply
    690.55x = 1,035.80 × 279.68
  4. Step 4: Simplify right side
    690.55x = 289,688.06
  5. Step 5: Solve for x
    x = 289,688.06/690.55
  6. Step 6: Final answer
    x = 419.50

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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.