Upcoming Maths Test Revision (Cirlces)

Formula for Circumfernece

Pi x d

Formula for Area

Pi x r²

Define a sector of a circle

2 radii connected by an arc

Formula to find the area of a sector of a circle

Pi x r² x (Angle/360)

Define an arc of a circle

A part of the circumference of a circle

Formula to find the distance of the arc

Pi x d x (Angle / 360)

Define a Tangent

A line that touches the edge of a circle

Define the radius of a circle

A line going from centre to rim. 2 of these is equal to a diameter

Define a Chord in a circle

Two points on the edge of a circle joined together to make a line. The area within the line creates a Segment

How do you find the area of a rectangle?

L x W

How do you find the area of a triangle

B x H x ½

How to find the area of a parallelogram

B x H

How to find the area of a trapezium

½(A + B) x h

How do you find the perimeter of any shape

Add up all of the sides

Simplify 10 : 50

1 : 5

Simplify 36 : 42

6 : 7

Split £1000 in the ratio 5 : 15

£250 : £750

35% of 200

10% = 20

5% = 10

30% = 60

35% = 70

Formula to calculate Interest

New amount = Old Amount x (Multiplier) /\ Years invested

Increase 15 by 30%

15 × 1.3 = 19.5