Stuck on Pythagoras homeschool question

[Starlightstarbright1]

Can anyone help with with maths question . My son is stuck I have no idea

the square of the hypotenuse is equal to the sum of the squares of the other two sides. So 11squared equals 4 squared plus a-c squared. Rearrange it, square root it and its solved

label each side A, B and C. The longest side is C, so C= 11cm, and B= 4cm.
Now you put it into the equation, a² + b² = c² , so
a² + 4² = 11²
take 4² over to the other side, so
a² = 11² -4²
which would be
a² = 105
then square root 105 to give 10.25 (to 2dp)
so AC = 10.25 (2dp)

hopefully I did that right!

a2 + 42 = 11^2

a^2 + 16 = 121

a^2 = 121 -16

a^2 = 105

a = sqrt(105) do it on a calculator = ~10.something

If you knew it was Pythag, what were you stuck on (interested not being sarky)

This is the most basic possible Pythagoras question with no twist whatsoever so he really needs to go back to BBC Bitesize or whatever textbook/website he’s using and go through the topic from scratch.

missing ? in my post

When you've got a right angled triangle, then pythagoras theorem gives us a way of working out the length of the third side if you know the length of the other two.

The long side opposite the right angle is called the hypotenuse (I might have spelt this wrong!). It is AB in that diagram (because it's the line from A to B). The other sides are AC and CB.

Pythagoras theorem tells us this:

(AC squared) + (CB squared) = (AB squared).

So (AC squared) + (4 squared) = (11 squared)

So (AC squared) + 16 = 121

So (AC squared) = 121-16

So (AC squared) = 105

So AC = whatever the square root of 105 is (I'd need a calculator for that bit).

I don’t mean to be mean by the way - I normally love helping to explain slightly tricky maths homework questions, but in this case the only useful answer is “go back and study the Pythagoras topic until you understand it”

Thank you that works but then I do this .

8 squared is 64
22squared is 484

So 484 + 64 = is 548 which it says is wrong

You need to take the square root of 548

Got it needed to do square root

I work with pre school it is a very very long time since I have done this