Home / 386.31-579.34-129.75

Finding the Fourth Proportional to 386.31, 579.34 and 129.75

Calculator

Solution

The fourth proportional to 386.31, 579.34 and 129.75 is: 194.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.31 : 579.34 = 129.75 : x
  2. Step 2: Convert to fraction form
    386.31/579.34 = 129.75/x
  3. Step 3: Cross multiply
    386.31x = 579.34 × 129.75
  4. Step 4: Simplify right side
    386.31x = 75,169.37
  5. Step 5: Solve for x
    x = 75,169.37/386.31
  6. Step 6: Final answer
    x = 194.58

Related Problems

Find fourth proportional to 193.16, 289.67 and 64.88
Half scale
Find fourth proportional to 772.62, 1,158.68 and 259.50
Double scale
Find fourth proportional to 387.31, 580.84 and 130.75
Similar ratio
Find fourth proportional to 579.47, 869.01 and 194.63
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.