Jenny wants to show the gym on a scale drawing. She uses a scale of 1:75. The gym has a length of 12.3 metres. Jenny works out the length of the gym on the scale drawing is 18cm. Is she correct?

She is wrong

Step-by-step explanation:

Let us use the scale 1 : 75 to find the length of the gym on the scale drawing.

The scale means that 1 m on the drawing represents 75 m in real life.

Therefore, if the length of the gym is 12.3 cm, then the length of the gym in the scale drawing is:

12.3 / 75 = 0.164 m

Converting to cm:

1 m = 100 cm

0.164 m = 0.164 * 100 = 16.4 cm

She is wrong.

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.