2 years ago

Calculate the perimeter of a semi circle whose radius is 21cm

Mathematics

1 answer:

torisob [31]2 years ago

6 0

Radius of semicircle r = 21 cm

Perimeter of semicircle

= pi*r + 2r

= (22/7)*21 + 2*21

= 22*3 + 42

= 66 + 42

= 108 cm

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natima [27]

Answer:

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2 years ago

Find the TWO integers whos product is -12 and whose sum is 1<br>

julsineya [31]

Answer:

$\rm Numbers = 4 \ and \ -3.$

Step-by-step explanation:

Given :-

The sum of two numbers is 1 .

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And we need to find out the numbers. So let us take ,

First number be x

Second number be 1-x .

According to first condition :-

$\rm\implies 1st \ number * 2nd \ number= -12\\\\\rm\implies x(1-x)=-12\\\\\rm\implies x - x^2=-12\\\\\rm\implies x^2-x-12=0\\\\\rm\implies x^2-4x+3x-12=0\\\\\rm\implies x(x-4)+3(x-4)=0\\\\\rm\implies (x-4)(x+3)=0\\\\\rm\implies\boxed{\red{\rm x = 4 , -3 }}$