• Free
  • Grade 9
  • Special angles, surds exact

Exact trig values worksheets

The special angles — 0, 30, 45, 60 and 90 degrees — have exact values a student is meant to know by heart. These free printable worksheets ask for sin, cos and tan at each, left exact as a surd or a fraction rather than a decimal.

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Ready to printExact trig values
Exact trig values worksheet — Special angles, surds exact, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The values come straight off two triangles: the 30-60-90 with sides 1, √3, 2, and the 45-45-90 with sides 1, 1, √2. So sin 30° is 1/2, cos 45° is √2/2, tan 60° is √3 — read off the sides, never rounded. A calculator's 0.866 hides the √3/2 the student is supposed to recognise, which is why this page prints and keeps the answer exact.

Why this sheet works

The answers are stacked the way a book writes a fraction, and the step-by-step walk names the triangle each value comes from. Learning them is what makes the unit circle and later identities quick rather than a lookup every time.

How this one works

One question from this sheet, worked through a step at a time.

Find tan 60°

tan 60°=?
tan 60°=√3
  1. tan 60°: the 30-60-90 triangle has sides 1, √3, 2.
  2. So tan 60° = √3.