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Finding the Fourth Proportional to 145.21, 200.40 and 79.72

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Solution

The fourth proportional to 145.21, 200.40 and 79.72 is: 110.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.21 : 200.40 = 79.72 : x
  2. Step 2: Convert to fraction form
    145.21/200.40 = 79.72/x
  3. Step 3: Cross multiply
    145.21x = 200.40 × 79.72
  4. Step 4: Simplify right side
    145.21x = 15,975.89
  5. Step 5: Solve for x
    x = 15,975.89/145.21
  6. Step 6: Final answer
    x = 110.02

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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.