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Finding the Fourth Proportional to 987.39, 1,359.59 and 919.35

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Solution

The fourth proportional to 987.39, 1,359.59 and 919.35 is: 1,265.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.39 : 1,359.59 = 919.35 : x
  2. Step 2: Convert to fraction form
    987.39/1,359.59 = 919.35/x
  3. Step 3: Cross multiply
    987.39x = 1,359.59 × 919.35
  4. Step 4: Simplify right side
    987.39x = 1,249,934.47
  5. Step 5: Solve for x
    x = 1,249,934.47/987.39
  6. Step 6: Final answer
    x = 1,265.90

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.