# Maths ---- a tricky Subject.....

• Apr 26th 2012, 09:54 PM
vigyan
Maths ---- a tricky Subject.....
How far is a chord length 8 cm from the centre of a circle of radius 5 cm?

2) Find the angle and also the shaded area of the circle, when AB=10CM and radius = 10 cm.
• Apr 26th 2012, 11:09 PM
Prove It
Re: Maths ---- a tricky Subject.....
Quote:

Originally Posted by vigyan
How far is a chord length 8 cm from the centre of a circle of radius 5 cm?

2) Find the angle and also the shaded area of the circle, when AB=10CM and radius = 10 cm.

1. The radius is 5cm, so we make an isosceles triangle with one side from the chord (8cm) and the other two sides from two radii (each 5cm).

Use Heron's Formula to evaluate the area of the triangle.

The evaluate the height of the triangle (which is equal to the distance that the chord is from the centre) using A = bh/2.
• Apr 27th 2012, 06:16 AM
Mytutoing
Re: Maths ---- a tricky Subject.....
Or form a right angle triangle using radium - center to one end of cord, center or circle to mid point of cord. You now have two sides of a RA triangel - 5 and 4 cm. Use pythag to find other side.
• Apr 27th 2012, 07:10 AM
Plato
Re: Maths ---- a tricky Subject.....
Quote:

Originally Posted by vigyan
How far is a chord length 8 cm from the centre of a circle of radius 5 cm?
2) Find the angle and also the shaded area of the circle, when AB=10CM and radius = 10 cm.

This webpage has all you need to do this sort of problem.