Everything Maths Grade 10

25 ◦

7

x

SOLUTION

Step 1: Identify the opposite and adjacent sides and the hypotenuse with reference to the given angle

Remember that the hypotenuse side isalwaysopposite the right angle, it never changes position. The opposite
side is opposite the angle we are interested in and the adjacent side is the remaining side.

cos=

adjacent

hypotenuse

cos 25 °=

7

x

Step 2: Rearrange the equation to solve forx

cos 25 °x=

7

x

x multiply both sides byx

xcos 25 °= 7

xcos 25 °

cos 25 °

=

7

cos 25 °

divide both sides bycos 25 °

x=

7

cos 25 °

Step 3: Use your calculator to find the answer

x=

7

0,90630...

=7,723645...

7,72

Worked example 6: Finding lengths

QUESTION

Find the length ofxandyin the following right-angled triangle using the appropriate trigonometric ratio (round
your answers to two decimal places).

122 5.7. Solving trigonometric equations