rl^P:- V*;
and
{DG) = (DB).
v m + n
DIVISIONS OF
Since {DG) : (FB) = m : n,
(DB); (DG) = (m + n): m.
Now
(DB) = Y2?rh {a 2 + aaf + a' 2 )
m
FIGURES 343
(DG): {FB) = 4:1,
(DB): {DG) = 5:4.
(DR) = 5698,
(DG) = 4558f.
Let y be the height (CM) of the
cone CFG.
Then DH: AH = CK : KA,
or h:^{a — a') = {x + h):^a,
whence x is known.
Cone CDE=Y- n of 2 x,
cone CFG = (CDE) + ~ m —(DB),
v m + n
cone GAB= (CDE) + (DD).
Now, says Heron,
(CAB) + (CDE) _(x + h) 3 + x 3
{CFG) ” y 3
[He might have said simply
{CDE): {CFG) = x 3 : f.]
This gives y or Dili,
whence Xdf is known.
Now AD 2 = AH 2 + DH 2
= {-|(a —a/)} 2 + A 2 ,
so that HD is known.
Therefore DF = ^ .HD is
• h
known.
t 14.12
# + h = 3l - = 48,
and x = 48 — 12 = 36.
(cone CDE) = 4158,
(cone CFG) = 4158 + 4558f = 8716f,
(cone GAB) =4158 + 5698 = 9856.
8 71
y 3 - 5 _ . (48 3 + 36 3 )
u 9856 + 4158 v ;
= 8716§ • -WoT 4 4- — 97805,
whence y — 46 approximately.
Therefore LM = y — x = 10.
HD 2 = (3i) 2 + i2 2
= 156|,
and HD = 12-|.
Therefore DF = . 12-|
= 10
T2‘