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Finding the Fourth Proportional to 98.70, 147.50 and 87.90

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Solution

The fourth proportional to 98.70, 147.50 and 87.90 is: 131.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.70 : 147.50 = 87.90 : x
  2. Step 2: Convert to fraction form
    98.70/147.50 = 87.90/x
  3. Step 3: Cross multiply
    98.70x = 147.50 × 87.90
  4. Step 4: Simplify right side
    98.70x = 12,964.81
  5. Step 5: Solve for x
    x = 12,964.81/98.70
  6. Step 6: Final answer
    x = 131.36

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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.