If
a
b
=

c
d
then, a × d = b × c

If
a
b
=

c
d
then, a × d = b × c

Solve for x if
5
x

=
10
16

The proportion becomes
5
8

=
10
16

5
x

=
10
16

Solve for n if
8
10

=
n
25

200
10

=
10n
10

If
a
b

=
c
d
then,

a + b
b

=
c + d
d

x  8
8

=
6
4

x  8 + 8
8

=
6 + 4
4

x
8

=
10
4

If
x
y

=
x
4
then, y = 4

For instance If
50
y

=
50
100
then, y = 100

If
18
y

=
x
y
then, x = 18

If
a
b

=
c
d
then,

a + c
b + d

=
a
b

a + c
b + d

=
a
b

Say you have
x + 2
8 + 4

=
x
8

It is equivalent to
x
8

=
2
4

Solve for x if
5
x

=
10
16

The proportion becomes
5
8

=
10
16

5
x

=
10
16

Solve for n if
8
10

=
n
25

200
10

=
10n
10

If
a
b

=
c
d
then,

a + b
b

=
c + d
d

x  8
8

=
6
4

x  8 + 8
8

=
6 + 4
4

x
8

=
10
4

If
x
y

=
x
4
then, y = 4

For instance If
50
y

=
50
100
then, y = 100

If
18
y

=
x
y
then, x = 18

If
a
b

=
c
d
then,

a + c
b + d

=
a
b

a + c
b + d

=
a
b

Say you have
x + 2
8 + 4

=
x
8

It is equivalent to
x
8

=
2
4

Oct 22, 18 04:14 PM
Take a good look at these optical illusions with geometry
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
Oct 22, 18 04:14 PM
Take a good look at these optical illusions with geometry
Our Top Pages
Formula for percentage
Compatible numbers
Basic math test
Basic math formulas
Types of angles
Math problem solver
Algebra word problems
Surface area of a cube
Finding the average
Scale drawings
Everything you need to prepare for an important exam!
K12 tests, GED math test, basic math tests, geometry tests, algebra tests.
Real Life Math Skills
Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.