23
14
Finding the area of a triangle
In general, when the length of the base and the height of a triangle are known, its area can be
calculated by (Length of base)×(Height)÷2 . However, it is also possible to determine
the area given the lengths of the three sides, using the following formula.
Let the lengths of the three sides be , and ,
and set . The area
S
is
calculated:
Program
?→ A:?→ B:?→ C:(A + B + C)÷2→ D:√(D(D - A)(D - B)(D-C))
→ M:M < 47 STEP >
OUTPUT M : the area of a triangle
Execution Example:
Find the area of the right-angled triangle with sides of length 3 , 4 and 5 .
(The answer may also be calculated as: 3×4÷2=6 )
B
C
A
S
BC
DABC++()2÷=
SDDA–()DB–()DC–()=
ON
MODE MODE MODE
1
PRGM
MODE
1
COMP
1
P1
Prog
1
S A
D R
P1
P2 P3 P4
G
3
EXE
S A
D R
P1
P2 P3 P4
G
4
EXE
S A
D R
P1
P2 P3 P4
G
5
EXE
M
S A
D R
P1
P2 P3 P4
G
関数電卓事例集 .book 23 ページ 2002年9月4日 水曜日 午後12時55分