AimMent

For Class 8, 9 & 10

Foundation - a strong base in Physics, Chemistry, Maths & Biology

Concept-first questions with clear model answers across all four subjects, aligned to NCERT. Start early, build the habit, and walk into your board exams, NEET and JEE already ahead.

Class 824Class 924Class 1036
SubjectAllPhysics 19Chemistry 19Biology 19Mathematics 27
ChapterAllAcids, Bases and SaltsArithmetic ProgressionsCarbon and its CompoundsChemical Reactions and EquationsCirclesControl and CoordinationCoordinate GeometryElectricityHeredity and EvolutionHow do Organisms ReproduceIntroduction to TrigonometryLife ProcessesLight - Reflection and RefractionMagnetic Effects of Electric CurrentMetals and Non-metalsOur EnvironmentPair of Linear Equations in Two VariablesPolynomialsProbabilityQuadratic EquationsReal NumbersSome Applications of TrigonometryStatisticsSurface Areas and VolumesThe Human Eye and the Colourful WorldTriangles

Showing 1 question for Class 10. Tap a card to reveal the answer.

MathematicsTrianglesmedium

State the Basic Proportionality Theorem (Thales' theorem).

Reveal answer ↓

What it is

A line parallel to one side of a triangle cuts the other two sides in the same ratio.

Answer

The Basic Proportionality Theorem states that if a line is drawn parallel to one side of a triangle to intersect the other two sides at distinct points, then it divides those two sides in the same ratio. In triangle ABC, if DE is parallel to BC and meets AB at D and AC at E, then AD/DB = AE/EC.

If DE || BC then AD/DB = AE/EC

  • •Line parallel to one side of a triangle
  • •Divides the other two sides in the same ratio
  • •AD/DB = AE/EC
  • •Basis of similarity of triangles

Why learn this

It's the basis of similarity, scale drawings, maps and finding heights from shadows.

💡 Memory trick

Parallel line inside a triangle -> equal ratios: AD/DB = AE/EC.