Home / 122.70-169.23-78.42

Finding the Fourth Proportional to 122.70, 169.23 and 78.42

Calculator

Solution

The fourth proportional to 122.70, 169.23 and 78.42 is: 108.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.70 : 169.23 = 78.42 : x
  2. Step 2: Convert to fraction form
    122.70/169.23 = 78.42/x
  3. Step 3: Cross multiply
    122.70x = 169.23 × 78.42
  4. Step 4: Simplify right side
    122.70x = 13,271.02
  5. Step 5: Solve for x
    x = 13,271.02/122.70
  6. Step 6: Final answer
    x = 108.16

Related Problems

Find fourth proportional to 61.35, 84.62 and 39.21
Half scale
Find fourth proportional to 245.40, 338.46 and 156.84
Double scale
Find fourth proportional to 123.70, 170.61 and 79.42
Similar ratio
Find fourth proportional to 184.05, 253.85 and 117.63
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.