Question

9. Two sides of a triangle art 60cm and 100 cm. if its perimeter is 300 cm. then the third side
will be -
a. 60cm b. 100cm
c. 140cm
d. 40cm
10. Write the formula of total surface area of cone,​

Answer 1

hope this answer will be helpful ❤❤

Answer 2

$Given \: two \:sides \:of \: a \: triangle \:are \\60\:cm \: and \: 100\:cm$

$Let \: length \: of \: the \: third \:side = x \:cm$

$Perimeter \:of \:the \: triangle = 300\:cm$

$Sum \: of \: three \:sides = 300\:cm$

$\implies 60 \:cm + 100\:cm + x \:cm = 300\:cm$

$\implies 160\:cm + x \:cm = 300\:cm$

$\implies x = 300 - 160$

$\implies x = 140\:cm$

$Length \:of \: third \:side = 140\:cm$

Therefore.,

$Option \: \pink { ( c ) } \:is \: correct.$

$10. Let \: r \:and \: l \:are \: radius \:and \\slant \:height \:of \: a \: cone \: respectively .$

$\boxed { \pink { TSA \:of \:a \:cone = \pi r( r + l ) }}$

$where , TSA = Total \: surface \:area$

$and \: l = \sqrt{ r^{2} + h^{2} },\\Where , h = vertical \: height \:of \:the \:cone$

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