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Finding the Fourth Proportional to 1,980.32, 2,970.80 and 612

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Solution

The fourth proportional to 1,980.32, 2,970.80 and 612 is: 918.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,980.32 : 2,970.80 = 612 : x
  2. Step 2: Convert to fraction form
    1,980.32/2,970.80 = 612/x
  3. Step 3: Cross multiply
    1,980.32x = 2,970.80 × 612
  4. Step 4: Simplify right side
    1,980.32x = 1,818,129.60
  5. Step 5: Solve for x
    x = 1,818,129.60/1,980.32
  6. Step 6: Final answer
    x = 918.10

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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.