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Finding the Fourth Proportional to 990.40, 1,482.08 and 643.52

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Solution

The fourth proportional to 990.40, 1,482.08 and 643.52 is: 962.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.40 : 1,482.08 = 643.52 : x
  2. Step 2: Convert to fraction form
    990.40/1,482.08 = 643.52/x
  3. Step 3: Cross multiply
    990.40x = 1,482.08 × 643.52
  4. Step 4: Simplify right side
    990.40x = 953,748.12
  5. Step 5: Solve for x
    x = 953,748.12/990.40
  6. Step 6: Final answer
    x = 962.99

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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.