Home / 137.61-206.19-86.31

Finding the Fourth Proportional to 137.61, 206.19 and 86.31

Calculator

Solution

The fourth proportional to 137.61, 206.19 and 86.31 is: 129.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.61 : 206.19 = 86.31 : x
  2. Step 2: Convert to fraction form
    137.61/206.19 = 86.31/x
  3. Step 3: Cross multiply
    137.61x = 206.19 × 86.31
  4. Step 4: Simplify right side
    137.61x = 17,796.26
  5. Step 5: Solve for x
    x = 17,796.26/137.61
  6. Step 6: Final answer
    x = 129.32

Related Problems

Find fourth proportional to 68.81, 103.10 and 43.16
Half scale
Find fourth proportional to 275.22, 412.38 and 172.62
Double scale
Find fourth proportional to 138.61, 207.69 and 87.31
Similar ratio
Find fourth proportional to 206.42, 309.29 and 129.47
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.