Question

The angles in a triangle are in the ratio 1:2:3. Show that this triangle is a right-angled triangle. The hypotenuse of the triangle is 19 cm long. Calculate the length of the shortest side in the triangle

Answer 1

Answer:

see explanation

Step-by-step explanation:

(a)

Sum the parts of the ratio , 1 + 2 + 3 = 6 parts

Divide sum of angles in a triangle by 6 to find the value of one part of the ratio.

180° ÷ 6 = 30° ← value of 1 part of the ratio

2 parts = 2 × 30° = 60°

3 parts = 3 × 30° = 90°

Since there is an angle of 90° then the triangle is right.

(b)

The shortest side is the side opposite the smallest angle of 30°

Using the sine ratio and the exact value

sin30° = $\frac{1}{2}$ , then

sin30° = $\frac{opp}{hyp}$ = $\frac{opp}{19}$ = $\frac{1}{2}$ ( cross- multiply )

2 opp = 19 ( divide both sides by 2 )

opp = 9,5

Shortest side in the triangle is 9.5 cm