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Finding the Fourth Proportional to 280.25, 420.35 and 74.84

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Solution

The fourth proportional to 280.25, 420.35 and 74.84 is: 112.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.25 : 420.35 = 74.84 : x
  2. Step 2: Convert to fraction form
    280.25/420.35 = 74.84/x
  3. Step 3: Cross multiply
    280.25x = 420.35 × 74.84
  4. Step 4: Simplify right side
    280.25x = 31,457.31
  5. Step 5: Solve for x
    x = 31,457.31/280.25
  6. Step 6: Final answer
    x = 112.25

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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.