Question

Which one of the following is the longest length?

A) 840 m
B) 0.084 km
C) 8.4 × 10⁹ nm
D) 8.4 × 10⁷ μm

Answer 1

To find the longest length, all options are converted to meters. Option A (840 m) is the longest when compared to the converted lengths of the other options: B (84 m), C (8.4 m), and D (84 m).

Step-by-step explanation:

We are asked to compare different lengths and find the longest length. We'll need to convert each option to the same unit, the meter, for an accurate comparison:

• Option A: 840 m is already in meters, so no conversion is needed.
• Option B: 0.084 km is equivalent to 0.084 x 1000 m = 84 m, because there are 1000 meters in a kilometer.
• Option C: 8.4 x 109 nm to meters is calculated by dividing by 109, because there are 109 nanometers in a meter. This gives us 8.4 m.
• Option D: 8.4 x 107 μm (micrometers) is equivalent to 8.4 x 107 x 10-6 m = 84 m, as there are 106 micrometers in a meter.

Comparing these lengths, we can see that Option A (840 m) is the longest length.