Q 1) The Perimeter of triangle is 72cm and its sides are in the ratio 3:4:5 . Find it’s area and the Length of the altitude Corresponding to the longest side .
Q2) Find the base of an isosceles triangle whose area is 192cm² and the Length of one of the equal sides is 20cm.
Answer:
hii
Step-by-step explanation:
see answer above
so nice
☞︎︎︎ Solution :
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↬ Q1)
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↱ Given :
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➝ Let the constant of proportionality be = k
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⇒ 3k + 4k + 5k = 72cm
⇒ 12k = 72cm
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[tex] \large \: ⇒ \rm \: k = \dfrac{72}{12} [/tex]
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[tex] \boxed{ \large \therefore \underline{\: \rm \: k = 6cm}}[/tex]
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↦ The sides are –
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➢ Herons Formula :
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[tex] \large \mapsto \boxed{\: \mathtt{ \sqrt{s(s – a)(s – b)(s – c)} }}[/tex]
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[tex] \large = \rm \mathtt{ \sqrt{36(36 – 18)(36 – 24)(36 – 30)} }[/tex]
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[tex] \large ⇒ \mathtt{ \sqrt{36(18)(12)(6)} }[/tex]
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[tex] \large ⇒ \mathtt{ \sqrt{(648)(72)} }[/tex]
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[tex] \large ⇒ \mathtt{ \sqrt{(46656)} }[/tex]
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⇢ 216cm²
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➣ Finding altitude :
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➦ We know ,
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[tex] \: \: \: \: \: \: \: \: \: [/tex] Area of triangle =
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[tex] \large ➬ \: \boxed{ \: \: \mathtt{ \dfrac{1}{2} \times base \times height}}[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{1}{2} \times 30 \times h = 216 {cm}^{2} }[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{1}{ \cancel2} \times \cancel{30} \: 15 \times h = 216 {cm}^{2} }[/tex]
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[tex] \large⇒ \: \mathtt{h \: = \dfrac{216}{15} } \\ \\ [/tex]
[tex] \boxed{\boxed{ \large \therefore \: \underline{\tt{altitude = 14.4cm}}}}[/tex]
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_____________________________________________
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↬ Q2 )
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↱ Given :
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[tex] \large⇒ \: \mathtt{h = \sqrt{b – \dfrac{ {a}^{2} }{4} } }[/tex]
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[tex] \: \: \: \: \: \: \: \: \: [/tex] Area of triangle =
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[tex] \large ➬ \: \boxed{ \: \: \mathtt{ \dfrac{1}{2} \times base \times height}}[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{1}{2} \times a\times h = \dfrac{1}{2} \times a \times \sqrt{b – \dfrac{ {a}^{2} }{4} } }[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{1}{2} \times {a}^{2} \times \sqrt{ \dfrac{ {b}^{2} }{ {a}^{2} } – \dfrac{1}{4} } }[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{1}{2} \times {x}^{2} \times \sqrt{ \dfrac{ {20}^{2} }{ {x}^{2} } – \dfrac{1}{4} } }[/tex]
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[tex] \large⇒ \mathtt{ \dfrac{ {x}^{2} }{2} \times \sqrt{ \dfrac{ {1600} – {x}^{2} }{ {4x}^{2} } } }[/tex]
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[tex] \large⇒ 192 { \rm \: cm }^{2} = \\ \\ \large \: \: \: \: \: \mathtt{ \dfrac{ {x}^{2} }{2} \times \sqrt{ \dfrac{ {1600} – {x}^{2} }{ {4x}^{2} } } }[/tex]
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[tex] \large⇒ 192 { }^{2} = \large \ \mathtt{ \dfrac{ {x}^{2} }{2} \times { \dfrac{ {1600} – {x}^{2} }{ {4x}^{2} } } }[/tex]
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⇒ 192² × 16 = x²(1600 – x²)
⇒ x⁴ – 1600x² + 589824 = 0
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★ Splitting The Middle Term –
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⇒ t² – 1600t + 589824 = 0
⇒ t² – 1024t – 576t + 589824 = 0
⇒ t(t – 1024) – 576(t – 1024) = 0
⇒ t = 1024 or 576
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[tex] \large⇒ \: \mathtt{ {x}^{2} = 1024 \: \: \: or \: \: \: 576}[/tex]
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[tex] \large⇒ \: \mathtt{ {x}^{} = \sqrt{ 1024 }\: \: \: or \: \: \: \sqrt{ 576}}[/tex]
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[tex] \large{ \boxed{\therefore \underline{\: \mathtt{ {x}^{} = 32cm \: \: \: or \: \: \:24cm} }}}[/tex]