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Finding the Fourth Proportional to 1,315.68, 1,973.18 and 390.99

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Solution

The fourth proportional to 1,315.68, 1,973.18 and 390.99 is: 586.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,315.68 : 1,973.18 = 390.99 : x
  2. Step 2: Convert to fraction form
    1,315.68/1,973.18 = 390.99/x
  3. Step 3: Cross multiply
    1,315.68x = 1,973.18 × 390.99
  4. Step 4: Simplify right side
    1,315.68x = 771,491.69
  5. Step 5: Solve for x
    x = 771,491.69/1,315.68
  6. Step 6: Final answer
    x = 586.38

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1.5x scale

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.