Home / 125.30-172.85-78.62

Finding the Fourth Proportional to 125.30, 172.85 and 78.62

Calculator

Solution

The fourth proportional to 125.30, 172.85 and 78.62 is: 108.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.30 : 172.85 = 78.62 : x
  2. Step 2: Convert to fraction form
    125.30/172.85 = 78.62/x
  3. Step 3: Cross multiply
    125.30x = 172.85 × 78.62
  4. Step 4: Simplify right side
    125.30x = 13,588.21
  5. Step 5: Solve for x
    x = 13,588.21/125.30
  6. Step 6: Final answer
    x = 108.45

Related Problems

Find fourth proportional to 62.65, 86.42 and 39.31
Half scale
Find fourth proportional to 250.59, 345.69 and 157.23
Double scale
Find fourth proportional to 126.30, 174.22 and 79.62
Similar ratio
Find fourth proportional to 187.94, 259.27 and 117.92
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.