the area if an isosceles triangle is 240 cm and the length of each one of its equal side is 26 cm . find the base of the triangle.
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given,
area of the ∆ABC =240cm²
let AB=AC=26cm
draw a AD is perpendicular to BC
let CD be x ,AD be h
area of ∆ADC=1/2*CD*AD
=> ar(ABC)/2=1/2*x*h
=>240/2=1/2*x*h
=>xh=240
=>h=240/x
by Pythagoras thereon,
AC²=AD²+CD
=>26²=h²+x²
=>676=(240/x)²+x²
=>676=57600/x²+x²
=>676=57600+x⁴/x²
=>x⁴-676x²+57600=0
let p=x²
=>p²-676p+57600=0
=>p=(-(-676))±√(-676)²-4(1)(57600)/2
=>p=676±√456976-230400/2
=>p=676±√226576/2
=>p=676±√(476)²/2
=>p=676±476/2
=>p=676+476/2 or 676-476/2
=>p=1152/2 or 200/2
=>p=576 or 100
=>p=x²=576 or 100
=>x=√576 or √100
=>x=24 or 10
=>CD=24 or 10
BC=BD+CD
=CD+CD. ( the AD divides the BC into two equal parts.)
=24+24,10+10
=48 or 20
the possible values of base is 48 and 20
HOPE IT IS HELPFUL TO U
pls mark it as brainliest.
area of the ∆ABC =240cm²
let AB=AC=26cm
draw a AD is perpendicular to BC
let CD be x ,AD be h
area of ∆ADC=1/2*CD*AD
=> ar(ABC)/2=1/2*x*h
=>240/2=1/2*x*h
=>xh=240
=>h=240/x
by Pythagoras thereon,
AC²=AD²+CD
=>26²=h²+x²
=>676=(240/x)²+x²
=>676=57600/x²+x²
=>676=57600+x⁴/x²
=>x⁴-676x²+57600=0
let p=x²
=>p²-676p+57600=0
=>p=(-(-676))±√(-676)²-4(1)(57600)/2
=>p=676±√456976-230400/2
=>p=676±√226576/2
=>p=676±√(476)²/2
=>p=676±476/2
=>p=676+476/2 or 676-476/2
=>p=1152/2 or 200/2
=>p=576 or 100
=>p=x²=576 or 100
=>x=√576 or √100
=>x=24 or 10
=>CD=24 or 10
BC=BD+CD
=CD+CD. ( the AD divides the BC into two equal parts.)
=24+24,10+10
=48 or 20
the possible values of base is 48 and 20
HOPE IT IS HELPFUL TO U
pls mark it as brainliest.
nikki1231:
pls mark it as brainliest
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