Home / 500.78-691.13-279.75

Finding the Fourth Proportional to 500.78, 691.13 and 279.75

Calculator

Solution

The fourth proportional to 500.78, 691.13 and 279.75 is: 386.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.78 : 691.13 = 279.75 : x
  2. Step 2: Convert to fraction form
    500.78/691.13 = 279.75/x
  3. Step 3: Cross multiply
    500.78x = 691.13 × 279.75
  4. Step 4: Simplify right side
    500.78x = 193,346.91
  5. Step 5: Solve for x
    x = 193,346.91/500.78
  6. Step 6: Final answer
    x = 386.09

Related Problems

Find fourth proportional to 250.39, 345.57 and 139.88
Half scale
Find fourth proportional to 1,001.57, 1,382.27 and 559.51
Double scale
Find fourth proportional to 501.78, 692.51 and 280.75
Similar ratio
Find fourth proportional to 751.17, 1,036.70 and 419.63
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.