Question

In right angled triangle PQR,PQ=square root of 15,QR= square root of 9,PR= square root of 6,which angle is of 90⁰,

angleP

angleQ

angleR


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Answer 1

Step-by-step explanation:

Formula used:

Curved surface area of cone =\pi\:r\:l=πrl square units

l^2=h^2+r^2l

2

=h

2

+r

2

In right ΔPQR,

PR^2=PQ^2+QR^2PR

2

=PQ

2

+QR

2

20^2=PQ^2+16^220

2

=PQ

2

+16

2

400=PQ^2+256400=PQ

2

+256

400-256=PQ^2400−256=PQ

2

PQ^2=144PQ

2

=144

PQ=\sqrt{144}PQ=

144

PQ=12\:cmPQ=12cm

case(i): when the triangle is revolving about the side PQ

Curved surface area of cone =\pi\:r\:l=πrl

Curved surface area=\pi\:(16)\:(20)=π(16)(20)

case(ii): when the triangle is revolving about the side QR

Curved surface area of cone =\pi\:r\:l=πrl

Curved surface area=\pi\:(12)\:(20)=π(12)(20)

Now,

\frac{C.S.A(i)}{C.S.A(ii)}

C.S.A(ii)

C.S.A(i)

=\frac{\pi\:(16)\:(20)}{\pi\:(12)\:(20)}=

π(12)(20)

π(16)(20)

=\frac{16}{12}=

12

16

=\frac{4}{3}=

3

4

C.S.A(i) : C.S.A(ii) = 4:3

Answer 2

Answer:

angle R

Explanation:

angle R

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