# GRE FORMULAS TO REMEMBER

## Terms

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copy deck
HOW MANY DEGREES IN A RGHT ANGLE
90
HOW MANY DEGREES IN A STRAIGHT LINE
180
THERE ARE HOW MANY DEGREES INN A TRIANGLE
180
THERE ARE ______IN A CIRCLE
360
A FOUR SIDED FIGURE HAS HOW MANY DEGREES
360
WHEN TWO LINES INTERSECT ANGLES ACROSS FROM EACH OTHER (VERTICLE ANGLES) ARE
EQUAL
AREA OF A TRIANGLE FORMULA
1/2 BxH
THE PERIMETER OF ANY FIGURE IS
SUM OF ITS SIDES
ANGELS GREATER THAN 0 BUT LESS THAN 90 DEGREES ARE CALLED?
ACUTE ANGLES
ANGLES EQUAL TO 90 DEGREES ARE CALLED
RIGHT ANGELS
ANGELS THAT SUM UP TO 90 DEGREES ARE CALLED
COMPLEMENTARY ANGLES.
THINK OF C FOR CORNER (THE ANGLE FORMS A 90 DEGREE CORNER ANGLE)AND C FOR COMPLEMENTARY
AN ANGLE THAT IS GREATER THAN 90 DEGREES BUT LESS THAN 180 IS CALLED AN
OBTUSE ANGLE.
THINK OF OBTUSE AS OBESE(OR FAT)ANGLE
AN ANGLE THAT MEASURE EXACTLY 180 DEGREES IS CALLED A
STRAIGHT ANGLE
ANGLES THAT SUM UP TO 180 DEGREES ARE CALLED
SUPPLEMENTARY
HINTS
IF YOU'RE LIKELY TO GET COMPLEMENTARY AND SUPP ANGLES CONFUSED, THINK OF ALPHABET--C COMES BEFORE S AND 90 COMES BEFORE 180
ANGLES AROUND A POINT TOTAL
360
IN ANGLES AROUND A POINT
FIRST DEFINE THE POINT FORMED WHERE THE LINES CROSS.
THEN ANGLES THAT ARE OPPOSITE EACH OTHER HAVE EQUAL MEASURES AND ARE CALLED VERTICAL ANGLES
NOTE THAT ALL ODD AND EVEN NUMBERED ANGLES ARE EQUAL. DO NOT ZIG ZAG
EX.
A TRIANGLE WITH 3 EQ SIDES AND 3 EQ ANGLES IS CALLED
EQUILATERAL
A TRIANGLE WITH 2 EQ SIDES AND ANGLES IS CALLED A
ISOSCELES
ANGELS OPPEOSITE EQUAL ASIDES IN A ISOSCELES TRIANGLE ARE
EQUAL
IN ANY TYPE OF TRIANGLE, THE SUM OF THE INTERIOR ANGLES IS
180
THE MEASURE OF AN EXTERIOR ANGLE OF A TRIANGLE IS EQUAL
TO THE SUM OF THE TWO REMOTE INTERIOR ANGLES

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