Keith left his house for the grocery store to buy items for dinner. He rode his bike 2miles down one road, took a 90-degree turn, and rode another 2 miles down a different road before arriving at the store. If he had ridden directly to the grocery store, how much distance would he have saved? Round your answer to the nearest tenth.

1 answer

To find the distance Keith would have saved by riding directly to the grocery store instead of following the two roads, we can use the Pythagorean theorem.

Keith rode 2 miles down one road and then took a 90-degree turn to ride another 2 miles down a different road. This forms a right triangle, where:

  • One leg of the triangle (a) = 2 miles
  • The other leg of the triangle (b) = 2 miles

Using the Pythagorean theorem:

\[ c = \sqrt{a^2 + b^2} \]

Substituting in the values of \(a\) and \(b\):

\[ c = \sqrt{2^2 + 2^2} = \sqrt{4 + 4} = \sqrt{8} = 2\sqrt{2} \]

Calculating \(2\sqrt{2}\):

\[ 2\sqrt{2} \approx 2 \times 1.414 \approx 2.828 \]

Now, this is the distance Keith would have traveled directly to the grocery store.

The distance he actually rode is:

\[ 2 \text{ miles} + 2 \text{ miles} = 4 \text{ miles} \]

To find out how much distance he saved by taking a direct route, we subtract the direct distance \(c\) from the actual distance he rode:

\[ \text{Distance saved} = 4 - 2.828 \approx 1.172 \]

Rounding this to the nearest tenth gives:

\[ \text{Distance saved} \approx 1.2 \text{ miles} \]

Thus, the distance Keith would have saved is approximately 1.2 miles.