In a right-angled triangle ABC, the angle at B is 90° . If AB = 6 cm and BC = 8 cm, what is the distance between the centroid G and the orthocenter H?
- (a)5 cm
- (b)10⁄3 cm
- (c)8 cm
- (d)20⁄3 cm
Answer
Why
Correct — B. Locate each centre, then measure between them.
Orthocentre: the legs AB and BC are both altitudes, so they meet at H = B
Hypotenuse by Pythagoras: AC = √(6² + 8²) = √100 = 10 cm
Median from B to the midpoint M of AC: M is equidistant from A, B and C, so BM = AC ÷ 2 = 5 cm
Centroid: G lies two-thirds of the way from B to M, so BG = 2⁄3 × 5 = 10⁄3 cm
Distance: GH = GB = 10⁄3 cm → option (b)
Why the others are wrong
- (a)5 cm — 5 cm is the whole median BM, which is also the distance from H (at B) to the circumcentre M. The centroid sits only two-thirds of the way along it, at 10⁄3 cm.
- (c)8 cm — 8 cm is the leg BC, not a distance between centres. G lies on the median BM, which is only 5 cm long, so GH cannot exceed 5 cm.
- (d)20⁄3 cm — 20⁄3 cm is two-thirds of the hypotenuse (2⁄3 × 10). The 2 : 1 split belongs to the median BM = 5 cm, and 20⁄3 cm is longer than BM itself.
Concept
A triangle has several centres, each fixed by a different set of lines. The centroid G is where the medians meet, and it cuts each median 2 : 1 from the vertex.
The orthocentre H is where the altitudes meet. The circumcentre O is the point equidistant from all three vertices.
In a right-angled triangle, H is the right-angle vertex and O is the midpoint of the hypotenuse, so the median to the hypotenuse runs from H to O.
Check with the Euler line: H, G and O lie on one line with HG = 2 × GO. Here H = B and O = M, so HO = 5 cm and HG = 2⁄3 × 5 = 10⁄3 cm.
Key facts
- The centroid divides each median in the ratio 2 : 1, the longer part next to the vertex.
- In a right-angled triangle the orthocentre is the right-angle vertex.
- In a right-angled triangle the circumcentre is the midpoint of the hypotenuse, so the median to the hypotenuse is half the hypotenuse.
- On the Euler line the centroid divides HO so that HG = 2 × GO.
Study next
Common traps
- Placing the orthocentre inside the triangle out of habit: with a right angle at B it sits at B.
- Taking two-thirds of the hypotenuse instead of the median, which gives 20⁄3 cm.
Here the right angle fixes the orthocentre for free.
Triangle centres also appear at 19 Jan 2026, 11:00 AM, Maths Q.4 (the circumcentre of an equilateral triangle coincides with its centroid), and the centroid's 2 : 1 split of a median decides 11 Sep 2024, 16:00, Quant Q.8.
Related PYQs
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