diketahui kerucut luas selimut 66cm² panjang garis pelukisnya 7 cm hitunglah A jari jari B luas alas kerucut C luas permukaan kerucut

A)
Luas selimut = π x r x s
66 cm²          = 22/7 x r x 7 cm
         66 cm² = 22 cm x r
                r    = 66 : 22
                r    = 3 cm

B) Luas alas kerucut
  = π x r²
  = 3,14 x 3 cm x 3 cm
  = 28,26 cm²

C) Luas permukaan kerucut
  = π x r ( r + s )
  = 3,14 x 3 cm ( 3 cm + 7 cm )
  = 9,42 cm x 10 cm
  = 94,2 cm²

a)
Ls.kerucut = 66
phi x r x s = 66
22/7 x r x 7 = 66
22 x r = 66
r = 66 : 22
r = 3 cm

b)
La.kerucut
= phi x r²
= 3,14 x 3²
= 3,14 x 9
= 28,26 cm²

c)
Lp.kerucut
= phi x r x (r+s)
= 3,14 x 3 x (3+7)
= 9,42 x 10
= 94,2 cm²