What was Thales basic question?

Thales, it is said, was the first to ask the question, “What is the basic ‘stuff’ of the universe” and, according to Aristotle, claimed the First Cause was water because, among other attributes, water could change shape and move while still remaining unchanging in substance.

What is BPT theorem class 10th?

Basic proportionality theorem: If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points then the other two sides are divided in the same ratio.

How do you prove a right angle?

Proof of Right Angle Triangle Theorem

Theorem:In a triangle, if square of one side is equal to the sum of the squares of the other two sides, then the angle opposite the first side is a right angle.
To prove: ∠B = 90°
Proof: We have a Δ ABC in which AC2 = AB2 + BC2
Also, read:
c2 = a2 + b2
c = √(a2 + b2)
A = 1/2 b x h.

Does a square have two 90 degree angles?

Opposite sides of a square are both parallel and equal in length. All four angles of a square are equal (each being 360°/4 = 90°, a right angle). All four sides of a square are equal. The diagonals of a square are equal.

Can a rhombus have 4 right angles?

A square has two pairs of parallel sides, four right angles, and all four sides are equal. It is also a rectangle and a parallelogram. A rhombus is defined as a parallelogram with four equal sides. No, because a rhombus does not have to have 4 right angles.

What is an irregular 4 sided shape called?

Irregular Quadrilateral: a four-sided shape where no sides are equal in length and no internal angles are the same. All internal angles still add up to 360°, as with all other regular quadrilaterals.

Does a rectangle have all right angles?

The first special case is called a rectangle. By definition, a rectangle is a parallelogram because its pairs of opposite sides are parallel. A rectangle also has the special characteristic that all of its angles are right angles; all four of its angles are congruent.