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Finding the Fourth Proportional to 1,686.80, 2,528.40 and 646.40

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Solution

The fourth proportional to 1,686.80, 2,528.40 and 646.40 is: 968.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,686.80 : 2,528.40 = 646.40 : x
  2. Step 2: Convert to fraction form
    1,686.80/2,528.40 = 646.40/x
  3. Step 3: Cross multiply
    1,686.80x = 2,528.40 × 646.40
  4. Step 4: Simplify right side
    1,686.80x = 1,634,357.76
  5. Step 5: Solve for x
    x = 1,634,357.76/1,686.80
  6. Step 6: Final answer
    x = 968.91

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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.