Multiple choice

A snake entered a cave and crawled 100 m northwards. It turn 150° to the west and crawls 87 m straight. How far is the snake from his starting point at the opening of the cave? (Note: sin 30° = 0.50; cos 30° = 0.87).

  1. 25 m

  2. 50 m

  3. 75 m

  4. 100 m

  5. 150 m
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The snake actually moved in 30-60-90 triangle. The backward distance to the starting point is 100 sin30°. It is also possible to use the law of cosines: A2 = B2 + C2- 2BCcos(a).

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