In the 4th Grade ICSE Mathematics textbook, students are not typically introduced to trigonometry concepts or formulas. Trigonometry is usually covered in higher grades like 9th or 10th.

However, some basic trigonometry formulas include:
1. Sine formula: sinθ = opposite/hypotenuse
2. Cosine formula: cosθ = adjacent/hypotenuse
3. Tangent formula: tanθ = opposite/adjacent

These formulas are used to calculate the ratios of sides of a right-angled triangle in relation to its angles. Students will learn more about trigonometry in higher grades as they progress in their Mathematics education.