What is the complementary angle to 33 ?

Basically we need an angle that when we add it to 33 we get 90.

**Let's set it up and solve it algebraically, letting x be the missing angle and see what we get:**

What is the supplementary angle to 33 ?

Basically we need an angle that when we add it to 33 we get 180.

**Let's set it up and solve it algebraically, letting x be the missing angle and see what we get:**

Figure ABCD is congruent to figure EFGH

If B = 55, C = 45, and D = 30, what is the measure of G?

Since G corresponds
with C and the
figures are congruent, **then G
= C = 45 degrees.**

If AD = 10, EF = 15, and BC = 12, what is the length of EH?

Since side EH corresponds to side AD and the figures are congruent,

**then side EH = side AD = 10.**

Figure ABCDE is similar to figure FGHIJ.

If A = 30, C
= 40, and E =
50, what is the measure of F?

Since F corresponds
to A and the
figures are similar, **then F
= A = 30.**

If AE = 10, FJ = 20, and BC = 40, what is the length of GH?

Since side GH corresponds to side BC and the figures are similar to
each other, then GH and BC are in proportion to each other. Similarly,
FJ and AE are in proportion to each other. When setting up the proportion,
make sure that you set it up the same on both sides.

***Cross multiply**

Since 2 and 7
are alternate exterior angles and the two lines are parallel, **then 2
= 7 = 50 degrees.**

Since 3 and 6
are alternate interior angles and the two lines are parallel, **then 3
= 6 = 50 degrees.**

Since 1 and 5
are corresponding angles and the two lines are parallel, **then 1
= 5 = 130 degrees.**

Since 4 and 6 are not alternate exterior, alternate interior or corresponding angles, they are not guaranteed to be equal.

However, since 2
and 4 make a
straight angle (180 degrees) and 2
and 6 are corresponding
angles (which means they are equal), we can find the measure of 4.

Last revised on August 6, 2011 by Kim Seward.

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