Home / 83.79-125.40-81.63

Finding the Fourth Proportional to 83.79, 125.40 and 81.63

Calculator

Solution

The fourth proportional to 83.79, 125.40 and 81.63 is: 122.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.79 : 125.40 = 81.63 : x
  2. Step 2: Convert to fraction form
    83.79/125.40 = 81.63/x
  3. Step 3: Cross multiply
    83.79x = 125.40 × 81.63
  4. Step 4: Simplify right side
    83.79x = 10,236.40
  5. Step 5: Solve for x
    x = 10,236.40/83.79
  6. Step 6: Final answer
    x = 122.17

Related Problems

Find fourth proportional to 41.90, 62.70 and 40.82
Half scale
Find fourth proportional to 167.58, 250.80 and 163.26
Double scale
Find fourth proportional to 84.79, 126.90 and 82.63
Similar ratio
Find fourth proportional to 125.69, 188.10 and 122.45
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.