Trigonometry: Find the length of side x on the right-angled triangle.

To answer this question it is best to remember SOH CAH TOA.SOH: sin(angle)=opposite (length of side opposite the angle)/hypotenuse (length).CAH: cos(angle)=adjacent (length of side next to the angle)/hypotenuse.TOA: tan(angle)= opposite/adjacent.
In a question like this you will be given an angle within the triangle, for example 60 degrees, and the length of one side, for example the hypotenuse as 13cm. If the side labeled x is adjacent to the angle then we will use CAH: cos(angle)= adjacent side/hypotenuse
So, cos60= adjacent/13Rearrange the equation to get adjacent = cos60 x 13Answer= 6.5

MK
Answered by Molly K. Maths tutor

5836 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

f(x)= 5 - x and g(x)= 3x + 7. Simplify f(2x) + g(x-1) (2018 past paper question)


An isosceles triangle ABC has a perimeter of 16cm. AB = x+3, AC = x+4. Calculate the area of ABC.


Differentiate (2a+3)^5/2 with respect to a


Make x the subject of the formula 3(2x – y) = ax – 4


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning