Level 3
Some patterns of shaded and unshaded small triangles is given. The unshaded triangles are those which have at least one side on the edge of the big triangle. All of the other small triangles are shaded. The table below shows numbers of small triangles.
  1. Find the total number of triangles in Pattern 80.
  2. Find the number of shaded triangles in Pattern 40.
  3. Find the number of unshaded triangles in Pattern 50.
3 m
Level 2
The shaded figure is made up of 4 quarter arcs of radius 12 cm. Find its area. (Take π = 3.14)
2 m
Level 2
The figure is formed using four identical isosceles triangles. AGD, AFB, BEC and CHD. ABCD is a square where E, F, G and H are midpoints of its sides. Given FJ = CJ, HK = BK and AD = 14 cm, find the total area of the shaded parts.
2 m
Level 2
The figure is formed by a circle and an isosceles triangle where PQ = PR. The radius of the circle is 14 cm. Find the area of the shaded part. (Take π = 227)
2 m
Level 3 PSLE
Figure ABCDE has an area of 42 cm2. ABD and CBE are straight lines. Find the area of the shaded triangle BDE.
2 m