Saturday, April 21, 2018

P6 circles (fr pcs pp)

Haha... in case you are wondering  if the area of the circle in the centre is indeed the size of “1 leaf” shape, the answer is they are not exactly the same. They are just pretty close.
Here’s a proof that shows the leaf is 0.57R2, whereas the circle in the centre is 0.54R2.

In any case, to solve the original question, there is no need to prove that.
Given in the question that the centre circle is 1/5 the total shaded area, 
we can infer that the circle has the same area as 1 leaf.

P6 Ratio (fr pcs pp)

Saturday, April 7, 2018

P6 Numbers, money, H: area diag (psle, CSE)

Exploration of height and base of triangles

Sharing my new creation with Geogebra...
Have fun exploring heights and bases of a triangle! Suggested activities:
  • Observe that the triangle is made up of 3 lines: red, green and blue, hence it will have 3 possible bases.
  • Observe that the triangle is an acute triangle.
  • Slowly move Point B up and down, as you are doing so...
    • What do you notice about the 3 heights (red, green and blue dotted lines)?
      • They all "drop" from the apex perpendicularly "down" to their respective bases
      • They intersect one another.
    • Observe when the green and blue heights seem to "disappear' into blue and green bases