Home / 1,385.55-2,078.46-645

Finding the Fourth Proportional to 1,385.55, 2,078.46 and 645

Calculator

Solution

The fourth proportional to 1,385.55, 2,078.46 and 645 is: 967.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,385.55 : 2,078.46 = 645 : x
  2. Step 2: Convert to fraction form
    1,385.55/2,078.46 = 645/x
  3. Step 3: Cross multiply
    1,385.55x = 2,078.46 × 645
  4. Step 4: Simplify right side
    1,385.55x = 1,340,606.70
  5. Step 5: Solve for x
    x = 1,340,606.70/1,385.55
  6. Step 6: Final answer
    x = 967.56

Related Problems

Find fourth proportional to 692.78, 1,039.23 and 322.50
Half scale
Find fourth proportional to 2,771.10, 4,156.92 and 1,290
Double scale
Find fourth proportional to 1,386.55, 2,079.96 and 646
Similar ratio
Find fourth proportional to 2,078.33, 3,117.69 and 967.50
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.