Yr 8 Flashcards
a³ × a⁴
a⁷
(a³)⁴
a¹²
a³ ÷ a⁴
a‐¹
a⁰
1
What is the equation for sum of interior angles
Let n = number of sides of shape
180(n-2)
Equation for exterior angle?
180 - interior angle
Sum of exterior angles?
360°
How to work out number of sides from exterior angle?
360/exterior angle
What is the first significant figure? (Sig fig)
The first non-zero digit
Area of a triangle?
b = base
h= height
2
Equation for area of a parallelogram
bh
Equation for a trapezium?
a = shorter top side iykwim
2
Equation for circumference of a circle?
C = πd
Equation for diameter of a circle?
d = 2r
Equation for area of a circle?
A = πr²
Equation for a straight line?
y = mx + c
m = gradient
c = y intercept
How to calculate gradient?
Change in x
Which is the y axis
The up-down one
Which is the x axis?
The left-right one
Equation for (avg.) speed?
Distance/time
Volume of a prism?
Area of cross-section × length
Volume of a cylinder?
πr²h
SA of a cylinder?
2(πr²) + ch
OR
2(πr²) + πdh
OR
2(πr²) + π2rh
What is a multiplier
The number you multiply an original value by to get a new value
What is a 20% increase as a multiplier?
1.2
What is a 20% decrease as a multiplier?
0.8
What is a 20% decrease as a multiplier?
0.8
What is a 150% increase as a multiplier?
2.5
What is a 150% increase as a multiplier?
2.5
How to calculate original value?
Multiplier
Hoe to calculate percentage change
Original value
How do you describe a translation?
A translation by (x)
(y)
But it’s one big bracket
How to describe a reflection?
A reflection in the line..(line equation)
How to describe an enlargement?
An enlargement about the point (x,y) with scale factor (…)
Define congruent
Two shapes that are exactly the same shape and size
Define similar shapes
Two shapes in same shape but sized proportionally
How is scale factor calculated?
Ratio between 2 corresponding sides
(12/8 = scale factor of 1.5)
