--ANGLES IN PARALLEL LINES--
"IMPORTANT RULES TO REMEMBER!"
"Alternate angles are equal"
"Corresponding angles are equal"
"Angles at a point add up to 360°"
"Vertical opposite angles are equal"
"Angles on a straight line add up to 180°"
"Now refer to these rules and complete the worksheet below!"
--ANGLES IN QUADRILATERALS--
"A quadrilateral is a polygon with 4 sides, 4 vertices (corners), and 4 interior angles, and the most important RULE is that
'All 'interior' angles total 360°'"
"Now complete this worksheet."
(I) "We know that one of the missing angles is 72°; we have 75°; we have 72° + 75° + 3x + 180° - x = 327° + 2x = 360° ∴ x = 16.5°
-ANGLES IN IRREGULAR/REGULAR POLYGONS--
"An irregular polygon is a shape where the sides and angles are 'NOT ALL' equal." (Note: some can be equal, just not all), whereas "A regular polygon is a shape where all sides and angles are equal."
"INTERIOR Angles of an irregular/regular Polygon"
Rule: 'The sum of all its interior angles is equal to the number of sides, 'n' - 2, multiplied by 180°.
"Prove it, baldy!!!" "Ok, shorty, how many triangles do you see in the 6-sided polygon below?" and "How many degrees in a triangle are there?" and "Do you get it now?"
"Check this rule for yourself below!"
"EXTERIOR Angles of an irregular/regular Polygon"
Rule: The sum of all its exterior angles is always = 360°
"Check this rule for yourself below!"
"Now complete these worksheets."
TIP!!!: The lines with arrows are parallel, so you need to refer to the "Alternate angles are equal" rule above!!!
Not sure about question (J)? "We know that all interior angles add up to 6-2 * 180° = 720°, so working out the angles we already know we can say: 2x + 47 + 72 + 4x + 262 + 360 - 7x = 720. sp, -x + 741 = 720, therefore x = 21
--EXTRA, EXTRA!!!--