Answer: 25.2 km
<u>Explanation:</u>
3 blocks east and four blocks east = 7 blocks
1 block = 0.3 km --> 7 blocks = 2.1 km
12 times 2.1 km = 25.2 km
The power of the lens is 2 diopter means that this lens has a focal length of 1/2 meter.
The focal length = 1 ÷ ( the number of diopters)
If one's glass prescription shows that the power of the lens is 2 diopter it means that the person is far-sighted. It means if a person needs to see something which is quite distant then his eyes need extra lens power to focus on it. Moreover, if there's a sign convention it means '+' indicates a convex lens and '-' concave lens. Also in-camera close up lens are also measured in terms of diopter.
I hope this answer helps.
To learn more about lenses,
brainly.com/question/766997
brainly.com/question/17014859
The answer is A , the forces are balanced