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Finding the Fourth Proportional to 612.10, 918.15 and 438.40

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Solution

The fourth proportional to 612.10, 918.15 and 438.40 is: 657.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.10 : 918.15 = 438.40 : x
  2. Step 2: Convert to fraction form
    612.10/918.15 = 438.40/x
  3. Step 3: Cross multiply
    612.10x = 918.15 × 438.40
  4. Step 4: Simplify right side
    612.10x = 402,516.96
  5. Step 5: Solve for x
    x = 402,516.96/612.10
  6. Step 6: Final answer
    x = 657.60

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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.