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Mathematics

For the following figure, tan A = 1231\dfrac{2}{3} and tan B = 13\dfrac{1}{3}

For the following figure, tan A =1 2/3 and tan B = 1/3. Concise Mathematics Solutions ICSE Class 10.

Statement (1): x = 36 cm

Statement (2): tan A = 53=h9\dfrac{5}{3} = \dfrac{h}{9} ⇒ h = 15

tan B = hx+913=15x+9\dfrac{h}{x + 9} \Rightarrow \dfrac{1}{3} = \dfrac{15}{x + 9}

  1. Both the statements are true.

  2. Both the statements are false.

  3. Statement 1 is true, and statement 2 is false.

  4. Statement 1 is false, and statement 2 is true.

Heights & Distances

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Answer

Given,

tan A = 123=531\dfrac{2}{3} = \dfrac{5}{3} and tan B = 13\dfrac{1}{3}.

From figure,

tan A=h953=h9h=5×93h=5×3h=15 cmtan B=hx+913=15x+9x+9=15×3x+9=45x=459x=36 cm.\Rightarrow \text{tan A} = \dfrac{h}{9} \\[1em] \Rightarrow \dfrac{5}{3} = \dfrac{h}{9} \\[1em] \Rightarrow h = \dfrac{5 \times 9}{3} \\[1em] \Rightarrow h = 5 \times 3 \\[1em] \Rightarrow h = 15\text{ cm} \\[1em] \Rightarrow \text{tan B} = \dfrac{h}{x + 9}\\[1em] \Rightarrow \dfrac{1}{3} = \dfrac{15}{x + 9}\\[1em] \Rightarrow x + 9 = 15 \times 3 \Rightarrow x + 9 = 45 \Rightarrow x = 45 - 9 \Rightarrow x = 36 \text{ cm}.

∴ Both the statements are true.

Hence, option 1 is the correct option.

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