Biology maths question help pls

Hi let me come to your rescue, Freedah (after all, I am not known as 007 for nothing! )

Ok let us look at it logically - there are 4 stomata in the pic and they are in a rectangular area slightly wider horizontally than taller vertically. If you measure the two sides of that rectangle with a ruler:

Horizontal (length) = 95mm or 9.5 cm
Vertical (width) = 57 mm or 5.7 cm

If you look at the scale at the bottom (and measure it!), it is 57 mm long and represents 0.1mm of leaf distance.

so, taking the two measurements above, what is the leaf length and width in real life (before being magnified) Are you with me?

OK - so you work that out as follows:

Length = 95/57 X 0.1 = 0.167mm
Width (easy peasy lemon squeezy - sorry treating you like a baby lol!) of course the same as the scale given = 0.1mm

OK taking you back to SATs (year 7?) what is the area of a rectangle? Yes well done!: length X breadth.

So in our example area = 0.17 X 0.1 = 0.017 mm2

There are four stomata in this 0.017 mm2 and we need to work out how many in 1 mm2.

1 whole mm2 is you will agree much more than 0.017mm2.

So we place the bigger number on top (numerator)

No, of stomata in 1mm2 = 1.00/0.017 X 4

= 235 (ANSWER)

If you use one more decimal place: 1.00/0.0167 X 4
= 239

That wasn't too bad was it - piece of (chocolate) cake? Yummy!

M (Specialist biology tutor)