Home / 67.85-101.79-31.80

Finding the Fourth Proportional to 67.85, 101.79 and 31.80

Calculator

Solution

The fourth proportional to 67.85, 101.79 and 31.80 is: 47.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.85 : 101.79 = 31.80 : x
  2. Step 2: Convert to fraction form
    67.85/101.79 = 31.80/x
  3. Step 3: Cross multiply
    67.85x = 101.79 × 31.80
  4. Step 4: Simplify right side
    67.85x = 3,236.92
  5. Step 5: Solve for x
    x = 3,236.92/67.85
  6. Step 6: Final answer
    x = 47.71

Related Problems

Find fourth proportional to 33.92, 50.90 and 15.90
Half scale
Find fourth proportional to 135.69, 203.58 and 63.60
Double scale
Find fourth proportional to 68.85, 103.29 and 32.80
Similar ratio
Find fourth proportional to 101.77, 152.69 and 47.70
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.