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Finding the Fourth Proportional to 287.64, 430.80 and 143.40

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Solution

The fourth proportional to 287.64, 430.80 and 143.40 is: 214.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.64 : 430.80 = 143.40 : x
  2. Step 2: Convert to fraction form
    287.64/430.80 = 143.40/x
  3. Step 3: Cross multiply
    287.64x = 430.80 × 143.40
  4. Step 4: Simplify right side
    287.64x = 61,776.72
  5. Step 5: Solve for x
    x = 61,776.72/287.64
  6. Step 6: Final answer
    x = 214.77

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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.