On a map, 1 cm represents 30 km. Two cities on the map are 2.3 cm apart.
How far apart are the actual cities?

A. 2.3 km
B. 13 km
C. 30 km
D. 69 km

D. 69 Km

Step-by-step explanation:

Scaling

Maps usually represent real areas on the field, but since they cannot fit in pieces of paper, we use scales where sizes and distances are all proportional to the real measurements.

On the map of the question, we know 1 cm represents 30 Km. It means that we can know approximate real distances by measuring the distances on the paper or blueprints.

Two cities are 2.3 cm apart on the map, it means that they are really 2.3*30 =69 Km apart

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1