**TABLET** - Table used in the early series containing the fundamental arithmetic operations.

**TANGENT** - Line or surface that touches another line or surface at a single point without intersections.

**TANGRAM - **Set of specific graphic pieces that can be put together to assemble geometric figures. Widely used in practical geometry activities.

**TRY AND ERROR, KICK** - A problem solving strategy where a choice is made to make the result feasible. This is done several times until some conclusion is reached close to the goal of solving the problem.

**THEODOLITE** - Optical instrument for accurately measuring horizontal angles and vertical angles; widely used in topographic and geodetic works.

**THEOREM **- Proposition that, to become evident, needs demonstration.

**TERM **- One of the mathematical objects in an operation.

**TETRAHEDRON** - A polyhedron with 4 faces. If the tetrahedron is regular, it will have 4 congruent faces, 4 vertices and 6 congruent edges.

**TON - **(t) Measurement of mass where 1 tonne = 1000 kilograms.

**TOTAL **- The result of an addition, subtraction, multiplication, division.

**TRANSFER **- An instrument that serves to measure angles.

**TRANSITIVE - **On equal terms: if a = b and b = c, then a = c. In inequalities: if a> b and b> c, then a> c or if a <b and b <c, then a <c.

**TRANSLATION - **Move a figure so that all its points move in the same direction and direction keeping the distances between them. Geometric transformation that respects the characteristics already pointed out.

**TRAPEZOID** - which is shaped like a trapeze; trapezoidal.

**TRIGONOMETRY -** Branch of mathematics that studies in the triangle the relations between the measures of the sides and amplitude of the angles.

**TRIANGLE** - Three-sided polygon.

**ACUTANGLE TRIANGLE - **all internal angles are sharp, ie angle measurements are less than 90 °.

**EASTER TRIANGLE - **A way of arranging numbers (in the form of a triangle) where the start and end elements of each line are 1, and the other elements are obtained by summing the preceding element and what follows it in the previous line.

**EQUILATERAL TRIANGLE - **The three sides have equal measures (see animation below).

**SCALENE TRIANGLE - **The three sides have different sizes (see animation below).

**TRIANGLE ISÓ “SCELES - **Two sides have the same size (see animation below).

**OBTUSAN TRIANGLE - **An internal angle is obtuse, that is, it has an angle greater than 90 °.

**RECTANGLE TRIANGLE - **It has a right internal angle (90 degrees).

**TRINÔ ”MIO - **Polynomial with three terms, three monomials.

A - B - C - D - E - F - G - H - I / J / K - L - M - N - O - P - Q - R - S - T - U / V - X / Z