Question-149510

Question Number 149510 by Tawa11 last updated on 05/Aug/21

Commented by Ar Brandon last updated on 06/Aug/21

36 - 4 \times \frac{9}{2} = {18 cm}^{3}

Commented by Tawa11 last updated on 06/Aug/21

{cm}^{2} ?

And sir, how did you get 4 \times 5

Commented by Ar Brandon last updated on 06/Aug/21

Just some guess work, hahaha!

Maybe Mr W has a better method .

Commented by Tawa11 last updated on 06/Aug/21

Hahahaha \dots Thanks sir . I appreciate .

Commented by MJS_new last updated on 06/Aug/21

counting the white areas

(1) left upper corner 2 \times 2 = 4

(2) middle square + right lower corner 2 \times 2 = 4

(3) the symmetric small “ {triangles}^{″}

2 \times (2 \times 2 - 2^{2} π / 4) = 8 - 2 π

(4) the symmetric big “ {triangles}^{″}

2 \times (4 \times 4 - 4^{2} π / 4) = 32 - 8 π

sum of these = 48 - 10 π = white area

36 - (48 - 10 π) = 10 π - 12 = blue area

Commented by Tawa11 last updated on 06/Aug/21

Thanks sir . God bless you .

Commented by Tawa11 last updated on 07/Aug/21

Sir Mjs and ajfour . Thanks, I understand your solutions very well now .

God bless you .

Answered by ajfour last updated on 06/Aug/21

B = \frac{π}{2} {(4 c m)}^{2} - 2 {4 {c m}^{2} - \frac{π}{4} {(2 c m)}^{2}}

- 4 {c m}^{2}

= (10 π - 12) {c m}^{2}

Commented by Tawa11 last updated on 06/Aug/21

Thanks sir . God bless you .

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