Page 66 - Grade 10 C.Math

6.2 (a) uf]nfsf] ;txsf] If]qkmn (Surface area of sphere)

lj|mofsnfk 1 M
Jof; / prfO a/fa/ ePsf] Pp6f a]ngf

lng'xf];\ . ;f]xL a]ngfsf] Jof; a/fa/ Jof; ePsf]
Pp6f uf]nf klg lng'xf];\ . a]ngfsf] jj|m ;tx 9fSg] h = 2r
Curriculum Development Centre
u/L wfuf]n] a]g'{xf];\ . ;f]xL wfuf] lems]/ gbf]xf]l/g]
u/L uf]nfnfO{ a]g'{xf];\ . h;af6 a]ngfsf] jj|m
;txsf] If]qkmn / uf]nfsf] ;txsf] If]qkmn a/fa/
ePsf] b]lvG5 . t;y{ uf]nfsf] ;txsf] If]qkmn (a) c = 2r
= a]ngfsf] jj|m ;txsf] If]qkmn x'G5 .

= a]ngfsf] cfwf/sf] kl/lw x a]ngfsf] prfO
= c x h (c = a]ngfsf] cfwf/sf] kl/lw / h = a]ngfsf] prfO_
= c x d
= 2r x (2r) [ h = d = 2r, c = 2r)

= 4r 2

 uf]nfsf] k'/f ;txsf] If]qkmn (A) = 4r x'G5 .
2

lj|mofsnfk 2
Pp6f uf]nf lng'xf];\ / pSt uf]nfsf] Jof;

a/fa/sf] prfO / Jof; ePsf] Pp6f a]ngf lrqdf
.
b]vfPsf] h:t} u/L lgdf{0f ug'{xf];\ o;/L lgdf0f{ ul/Psf]
a]ngfleq uf]nf l7Ss c6\g ;S5 . ca a]ngfsf] h = 2r
prfOsf] dWo efuaf6 a]ngfnfO{ 3'dfpFb} uf]nfnfO{
x]g'{xf];\ . uf]nfsf] ;txnfO{ a]ngfsf] jj|m ;txn]
k'/} 3]l/Psf] b]lvG5 . t;y{ uf]nfsf] ;txsf] c = 2r
If]qkmn = a]ngfsf] jj|m ;txsf] If]qkmn = a]ngfsf]
cfwf/sf] kl/lw a]ngfsf] prfO

t;y{ uf]nfsf] ;txsf] If]qkmn (SA of sphere) = 4r ju{ PsfO
2
(b) uf]nfsf] cfotg (Volume of sphere)

lj|mofsnfk 1
a/fa/ Jof; ePsf Pp6f uf]nf / Pp6f a]ngf lng'xf];\ . a]ngfsf] Jof; / prfO klg
a/fa/ lng'k5{ . a]ngfdf kfgL eg'{xf];\ / pSt kfgLnfO{ gfKg] efF8f] (Measuring cylinder) df lj:tf/}

63 ul0ft, sIff – 10