# Help me with Maths IGCSE past paper?

Question 1: A is the point (7, 12) and B is the point (2, -1). Find the length of AB.

I'm in grade 10, and I dont think i have learnt it .. Could you show me the work and the solution?

And also I would like to know what topic its.

Thank uuu

### 8 Answers

- Wayne DeguManLv 72 months agoFavorite Answer
Co-ordinate geometry is the topic here.

It's a case of applying Pythagoras' theorem

If we sketch the diagram joining A to B and evaluate the difference in the x coordinates and y coordinates, we create a right-angled triangle.

Difference in x => 7 - 2 = 5

Difference in y => 12 - (-1) = 13

We then have AB² = 5² + 13²

so, AB² = 25 + 169 => 194

Hence, AB = √194 => 13.9 units

See diagram below.

:)>

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- lenpol7Lv 72 months ago
Use Pythagoras

AB^2 = (7-2)^" + (12 - - 1)^2

AB^2 = 5^2 + 13^2

AB^2 = 25 + 169

AB^2 = 194

AB = sqrt(194) = 13.928....

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- PhilomelLv 72 months ago
It is Pythagorean's theorem in geometry.

Go to KhanAcademy.org and learn math geometry, trig and algebra. It will take you ~ 1 year if you work at it. It is a series of videos and is very good. Make a notebook and keep notes as you go.

For this problem The length is sqrt[(7-2)^2+(12+1)^2]=sqrt[(5)^2+(13)^2)]=sqrt[25+169]=sqrt[194]=13.93

13.93 units

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- RealProLv 72 months ago
I must ask, did you make an attempt to look this up yourself?

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- KrishnamurthyLv 72 months ago
A is the point (7, 12) and B is the point (2, -1).

Find the length of AB.

Distance Formula:

Given the two points (x1, y1) and (x2, y2),

the distance d between these points is given by the formula:

d = sqrt{(x2 - x1)^2 + (y2 - y1)^2}

d = sqrt(25 +169) = sqrt 194 = 13.92838827718412

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- stanschimLv 72 months ago
d = √[ (y2 - y1)^2 + (x2 - x2)^2]

d = √[ (-1 - 12)^2 + (12 - 7)^2 ]

d = √[ (-13)^2 + (5)^2 ]

d = √ (169 + 25)

d = √ 194

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- Anonymous2 months ago
It's just using Pythagoras, which I'm sure you have covered.

Sketch xy axes and mark A and B.

Draw a vertical line through A.

Draw a horizontal line through B.

These lines meet at P (7,-1) and ABP is a right-angled triangle with AB the hypotenuse.

AB² = AP² + BP² = (7-2)² + (12-(-1))² = 194

AB = √194 = 13.9 approx,

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