Home / 55.65-76.80-31.09

Finding the Fourth Proportional to 55.65, 76.80 and 31.09

Calculator

Solution

The fourth proportional to 55.65, 76.80 and 31.09 is: 42.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.65 : 76.80 = 31.09 : x
  2. Step 2: Convert to fraction form
    55.65/76.80 = 31.09/x
  3. Step 3: Cross multiply
    55.65x = 76.80 × 31.09
  4. Step 4: Simplify right side
    55.65x = 2,387.37
  5. Step 5: Solve for x
    x = 2,387.37/55.65
  6. Step 6: Final answer
    x = 42.90

Related Problems

Find fourth proportional to 27.82, 38.40 and 15.54
Half scale
Find fourth proportional to 111.30, 153.59 and 62.17
Double scale
Find fourth proportional to 56.65, 78.18 and 32.09
Similar ratio
Find fourth proportional to 83.47, 115.19 and 46.63
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.