Calcolo del termine incognito di una proporzione
4 : x x = : 81 x: 15 :
4 1 7
= 3
5 : 14 11 : 7 3
2 = x
5 : 14 7
: 22 3
11 = x
1 4
1 : x x = : 25 75 49
3 : x x = : 16
6 , 1 : :
4 0 ,
0 x = x
x: 1 :
8 1 9
1 3
7 6
3 10
8
+ = + − 30
+ +
=
+ 30
8 10 : 3 6 7 3 1 9 1 8 : 1 x
10 7
3 8
2 7
5 6
1 4
2 3
1
⋅ − : x = + : − 8 10
7 3 8
2 7
5 6
1 4
2 3
1
⋅ − : x = + : − 8 3 2
3
1
4 2 1
− : x x = : ⋅ + 3 5
8 4 3
1 2
2 3
2
9 1 9
4 7 9
3 4
1
÷ − : x = − ⋅ + : ÷ + 8
1 3
7 14
8 5
1
15 1 1
3 5 1
+ ⋅ − : + = + 3 : x 1 2
5 1 7
7
5 1 2 5
1
2 2 2
− + ⋅ : − + = + 5 : x
2 3
1
3 2 1 4
5 3 1 1
5 2
2
3
− ÷
3: − ÷ = x : − ÷
1 1 4 5
5 34
1
3 1 1 2
1 5
2
: − ⋅ = − − + : x
3 4
1
2 3 10 2 1 1
2 1 3
8
3
+ ÷ : = + − ÷ − : x
3 14
9 28
10 9
4 5
1 2 21 50
7 6
1 5 2
4÷ + ÷ = −
÷ x ÷ +
( 1 3 0 3 0 46 , + , − , ) ( ÷ 3 2 2 7 , − , ) = ÷ x ( 0 2 0 6 , + , )
( 1 1 0 3 , − , ) ÷ = ÷ x x 2 + 2 7
Esercizi e soluzioni
5 8 4 10
: 10 4 : 5
⋅ =
=
= x
x
10 25 50 5
: 50 5 : 10
⋅ =
=
= x
x
1 42 2 21 19
38 21
38 : 19 : 21
⋅ =
⋅ =
=
= x
x
36 4 3 9
4 27 39
52 27
52 : 39 : 27
=
⋅
⋅ =
⋅ =
=
= x
x
4 : x x = : 81
18 9 2 81 4 81 4
81 4
=
⋅
=
⋅
=
⋅
=
÷
=
÷ x
x x
28 45 7 1 3 4 15 3 : 7 4 1 15 3 7 4 1 15
3 : 7 4 1 : 15
=
⋅
⋅
=
⋅
⋅ =
=
=
x x
5 : 14 11 : 7 3
2 = x
35 44 7 11 5 4 1 3
2
2=
⋅ / /
⋅ /
=
x
5 : 14 7
: 22 3
11 = x
35 49 2 2
7 5 4 1 3
1 1
2
7
=
/
⋅ / /
⋅ / /
= /
/
x
1 4
1 : x x = : 25
10 1 100
1 100
1 25
1 4 1
25 : 1 4 :
1
=
=
=
⋅
=
=
x
x x
75 49
3 : x x = : 16
28 15 4 7
15 16 49
225 16
49 225 16
3 49 75
16 : 3 49 :
75
⋅ =
⋅ =
⋅ =
=
⋅
=
=
x
x x
6 , 1 : :
4 0 ,
0 x = x
15 4 30
8 900
64 900
64 10
16 90
4 10 : 16 90 :
4
6 , 1 : : 4 0 , 0
=
=
=
=
⋅
=
=
=
x
x x
x x
− +
=
+ 30
8 10 : 3 6 7 3 1 9 1 8 : 1 x
24 255 1
15 24 17 1 15 1 3 72 17 1 30 6 9 72 17
30 : 1 6 9 72 : 17
30 8 : 9 6
7 2 72
8 : 9
30 8 10 : 3 6 7 3 1 9 1 8 : 1
=
⋅
=
⋅
⋅
=
⋅
⋅
=
=
−
= + +
− +
= +
x
x
x
x
+ +
=
+ : 10 30
6 3 9 : 8 x
8 5 24 15 1 15 24
1 1 30 2 3 72
1 17 30 6 9 72 17
30 : 17 6 9 72 : 17
30 8 : 9 6
7 2 72
8 : 9
30 8 10 : 3 6 7 3 1 9 1 8 : 1
=
=
⋅
=
⋅
⋅
=
⋅
⋅
=
=
+
= + +
+ +
= +
x x x x
10 7
3 8
2 7
5 6
1 4
2 3
1
⋅ − : x = + : − 8
8 1 3 1 12 24
3 1 8 2
7
24 : 13 12 : 13 28
7
24 3 : 16 12
3 : 10
28 8 15
24 3 : 16 12
3 : 10
7 2 4 3 7 5
4
1
=
/
⋅ / /
⋅ / / /
= /
=
−
= +
−
−
= +
−
⋅
x x
x x
3 2 3
1
4 2 1
− : x x = : ⋅ + 3
6 7 36 49 36
49 12
7 3 7
12 : 7 3 :
7
3 7 4 : 1 3 :
2 9
3 2 1 4 : 1 3 :
3 2
=
=
=
⋅
=
=
⋅
− =
+
⋅
=
−
x
x x
x x
x x
5 8
4 3
1 2
2 3
2
9 1 9
4 7 9
3 4
1
÷ − : x = − ⋅ + : ÷ + 8
!" # " " # " #
!
1 3
7 14
8 5
1
15 1 1
3 5 1
+ ⋅ − : + = + 3 : x
$ " " ! $ " # " !
! " !
" ! " !"
1 2 5
1 7
7
5 1 2 5
1
2 2 2
− + ⋅ : − + = + 5 : x
$ " $ " #
" #
" " "
x: 2 1 :
2 1 1
2 1 1
8 1 1 2
2 7
21 16
2
+ − − = − + − ⋅
$ # $ "
$ " # $ " #
# #
" " #
2 3
1
3 2 1 4
5 3 1 1
5 2
2
3
− ÷
3: − ÷ = x : − ÷
" # " # " #
# # ! #
" ! " #
1 1 4 5
5 34
1
3 1 1 2
1 5
2
: − ⋅ = − − + : x
" $ #
" $ "! #
" ! #
" ! #
3 4
1
2 3 10 2 1 1
2 1 3
+ ÷ : = + − ÷ − 8 : x
$ !# $ " " #
$ " # $ #
# #
" #
3 14
9 28
10 9
4 5
1 2 21 50
7 6
1 5 2
4÷ + ÷ = −
÷
÷ + x
2 3
10 9
8 5 10
9 25
21 16 16
9
3 10
3 5
21 16 4
3 21 16 2 7
2 3 5
+ ÷ = − ÷ ÷
÷ = ÷ ÷
= ⋅ ⋅ = = x
x
x ,
( 1 3 0 3 0 46 , + , − , ) ( ÷ 3 2 2 7 , − , ) = ÷ x ( 0 2 0 6 , + , )
12 9
3 10
42 90
29 9
25 9
2 10
6 10 120 27 42
90
29 25 9
2 6 10 105
90 4 9
8 10 21
18 4 9
4 5 7
6 4 5
9 4
21 10
7 6
2
3