Question

20. In a right angled triangle ABC,ZB = 90°. If AB =8em,
AC= 17cm find BC.
​

Answer 1

Answer:

The answer is=15 cm

Step-by-step explanation:

Here, we will use Pythagoras theorem,

So, according to Pythagoras theorem,

=(Height)^2+(Base)^2=(Hypotenuse)^2

=So, according to question;

=(AB)^2+(BC)^2=(AC)^2

=So,(BC)^2=(AC)^2-(BC)^2

= (BC)^2=(17)^2-(8)^2

=(BC)^2=289-64

=(BC)^2=225

=(BC) =√225

=(BC)=15 cm..

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Answer 2

$\large{\underline{\sf{\blue{Given-}}}}$

• $\sf{\angle \: B \: = 90°}$

• $\sf{AB \: = \: 8 \: cm}$

• $\sf{AC \: = \: 17cm}$

$\large{\underline{\sf{\red{To \: Find-}}}}$

• $\sf{BC \: = \: ?}$

$\large{\underline{\sf{\orange{Diagram-}}}}$

$\setlength{\unitlength}{2mm}\begin{picture}(0,0)\thicklines\put(0,0){\line(0,3){2.2cm}}\put(0,0){\line(3,0){1.8cm}}\put(9,0){\line(-5,6){1.8cm}}\put(-2,-2){\sf B}}\put(-2,11){\sf A}\put(10,-2){\sf C}\put(-5,5){\sf 8 cm}\put(6,5){\sf 17cm}\put(1,0){\line(0,2){2mm}}\put(0,1){\line(3,0){2mm}}\put(1,1){ \small\sf 90^\circ }\end{picture}$

$\large{\underline{\sf{\purple{Solution-}}}}$

$\sf\underline{We \: Know \: Pythagoras \: Theorem,}$

$\boxed{\sf \green{★ \: {AC}^{2} \: = \: {AB}^{2} + {BC}^{2} }}$

$\sf\underline{Placing \: Values,}$

$\sf\longrightarrow{ {17}^{2} = \: {8}^{2} + \: {(BC)}^{2} }$

$\sf\longrightarrow{189 = 64 + {(BC)}^{2} }$

$\sf\longrightarrow{( {BC)}^{2} = 189 + 64}$

$\sf\longrightarrow{( {BC)}^{2} = 225}$

$\sf\longrightarrow{( {BC)}^{2} = \sqrt{225} }$

$\boxed{\sf\red{★ \: BC = 15cm}}$

$\sf\therefore \: \underline{Length \: Of \: BC \: Is \: 15cm.}</p><p>$