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# What is the number of triangles that can be formed whose vertices are the vertices of an octagon but have only one side common with that of octagon?

 A) 64 B) 32 C) 24 D) 16

Explanation:

When the triangles are drawn in an octagon with vertices same as those of the octagon and having one side common to that of the octagon, the figure will appear as shown in (Fig. 1).

Now, we shall first consider the triangles having only one side AB common with octagon ABCDEFGH and having vertices common with the octagon (See Fig. 2).Such triangles are ABD, ABE, ABF and ABG i.e. 4 in number.

Similarly, the triangles having only one side BC common with the octagon and also having vertices common with the octagon are BCE, BCF, BCG and BCH (as shown in Fig. 3). i.e. There are 4 such triangles.

This way, we have 4 triangles for each side of the octagon. Thus, there are 8 x 4 = 32 such triangles.

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• Related Questions

Determine the number of rectangles and hexagons in the following figure.

 A) 30, 5 B) 32, 3 C) 28, 5 D) 30, 3

Answer & Explanation Answer: A) 30, 5

Explanation:

The figure may be labelled as shown

Rectangles :

The simplest rectangles are CVSR, VETS, RSWM and STKW i.e 4 in number.

The rectangles composed of two components each are CETR, VEKW, RTKM and CVWM i.e 4 in number.

The rectangles composed of three components each are ACRP, PRMO, EGHT and THIK i.e 4 in number.

The rectangles composed of four components each are CEKM, AVSP, PSWO,VGHS and SHIW i.e 5 in number.

The rectangles composed of five components each are AETP, PTKO, CGHR and RHIM i.e 4 in number.

The rectangles composed of six components each are ACMO and EGIK i.e 2 in number.

The rectangles composed of eight components each are AGHP, PHIO, AVWO and VGIW i.e 4 in number.

The rectangles composed of ten components each are AEKO and CGIM i.e 2 in number.

AGIO is the only rectangle having sixteen components

$\inline \fn_cm \therefore$ Total number of rectangles in the given figure = 4 + 4 + 4 + 5 + 4 + 2 + 4 + 2 + 1 = 30.

Hexagons :

The hexagons in the given figure are CDEKLM, CEUKMQ, CFHJMQ, BEUKNP and BFHJNP. So, there are 5 hexagons in the given figure.

Subject: Analytical Reasoning - Non Verbal Reasoning

4

Count the number of triangles and squares in the given figure.

 A) 36 triangles, 7 Squares B) 38 triangles, 9 Squares C) 40 triangles, 7 Squares D) 42 triangles, 9 Squares

Answer & Explanation Answer: C) 40 triangles, 7 Squares

Explanation:

The figure may be labelled as shown

Triangles :

The Simplest triangles are BGM, GHM, HAM, ABM, GIN, IJN, JHN, HGN, IKO, KLO, LJO, JIO, KDP, DEP, ELP, LKP, BCD and AFE i.e 18 in number

The triangles composed of two components each are ABG, BGH, GHA, HAB, HGI, GIJ, IJH, JHG, JIK, IKL, KLJ,LJI, LKD, KDE, DEL and ELK i.e 16 in number.

The triangles composed of four components each are BHI, GJK, ILD, AGJ, HIL and JKE i.e 6 in number.

$\inline \fn_cm \therefore$ Total number of triangles in the figure = 18 + 16 + 6 =40.

Squares :

The Squares composed of two components each are MGNH, NIOJ, and OKPL i.e 3 in number

The Squares composed of four components each are BGHA, GIJH, IKJL and KDEL i.e 4 in number

$\inline \fn_cm \therefore$ Total number of squares in the figure = 3 + 4 =7

Subject: Analytical Reasoning - Non Verbal Reasoning

4

Find the number of triangles in the given figure?

 A) 10 B) 12 C) 14 D) 16

Explanation:

The figure may be labelled as shown

The simplest triangles are ABJ, ACJ, BDH, DHF, CIE and GIE i.e 6 in number.

The triangles composed of two components each are ABC, BDF, CEG, BHJ, JHK, JKI and CJI i.e 7 in number.

There is only one triangle JHI which is composed of four components.

Thus, there are 6 + 7 + 1 = 14 triangles in the given figure.

Subject: Analytical Reasoning - Non Verbal Reasoning

6

Find the number of triangles in the given figure?

 A) 11 B) 13 C) 15 D) 17

Explanation:

We may label the figure as shown.

The Simplest triangles are AFB, FEB, EBC, DEC, DFB and AFD i.e 6 in number.

The triangles composed of two components each are AEB, FBC, DFC, ADE, DBE and ABD i.e 6 in number.

The triangles composed of three components each are ADC and ABC i.e 2 in number.

There is only one triangle i.e DBC which is composed of four components.

Thus, there are 6 + 6 + 2 + 1 = 15 triangles in the figure

Subject: Analytical Reasoning - Non Verbal Reasoning

1

What is the number of rectangles in the following figure?

 A) 6 B) 7 C) 9 D) 11

Explanation:

The simplest rectangles are AEHG, EFJH, FBKJ, JKCL and GILD i.e 5 in number.

The rectangles composed of two components each are AFJG and FBCL i.e 2 in number

Only one rectangle namely AFLD is composed of three components and only one rectangle namely ABCD is composed of five components.

Thus, there are 5 + 2 + 1 + 1 = 9 rectangles in the given figure.