Maths 3 marks

aking smaller triangles we have AFB, BFG, BGC, CGH, HCD, DHI, DIE, EIJ, EJA and AJF
⇒ 10 triangles.
Taking the combination of 2.
CGD, CID, DJE, DHE, EIA, EFA, AGB, AJB, BHC and BFC are 10 triangles.
Combining 3 at a time we have CED, DAE, EBA, ACB, BDC, CEF, DBJ, GDA, EBH, ACI
⇒ 10 triangles.
Other triangles are BCE, CAD, DBE, ADB and ACE are 5 triangles.
Total 10 + 10 + 10 + 5 = 35 triangles.

The smaller portions A, B, C, D, E, F, G and H are 8 triangles.
Combining 2 at a time B and C, D and F, F and G, A and H are 4 triangles.
Taking 4 at a time
Combination of B, C, C, D and E, D, E, F and G, F, G, H and A, H, A, B are 4 triangles.
Total triangles = 8 + 4 + 4 = 16.

Smaller squares 4 × 4 = 16 ...(As numbered)
As a whole bigger = 4
Total squares = 20

As we see in the figure in the middle 1, 2, 3, and 4 are 4 small squares.
Also, we have 9 and 10 = 2 big squares.
Outer squares 5, 6, 7, and 8 = 4.
Total = 4 + 4 + 1 + 1 = 10 squares.