Hi Diane!
Vertical angles are equal, so m∠CAT = m∠MAN
m∠CAT = 4(x+3)
m∠MAN = 3(2x-3)
m∠CAT = m∠MAN
4(x+3) = 3(2x-3)
4x+12 = 6x - 9 (multiply through parentheses)
-4x -4x (subtract 4x from both sides)
------------------
12 = 2x - 9
+9 +9 (add 9 to both sides)
--------------
21 = 2x
--- --- (divide both sides by 2)
2 2
21
--- = x
2
They're asking for the measure of
angle CAT (m∠CAT)
m∠CAT = 4(x+3)
21 3
= 4 ( -- + -- ) substitute 21/2 for x
2 1
21 3 2
= 4 ( --- + --- *--- ) get common denominator of 2
2 1 2
21 6
= 4 (---- + ---)
2 2
27
= 4( ---- )
2
27
= 2 4( ----) 4 divided by 2 is 2
2
= 2 (27)
= 54
The measure of ∠CAT = 54°