Chapter 4 of 515% of exam

Math — Geometry

Geometry questions test core formulas for area, the Pythagorean theorem, circles, and polygon angles. Memorizing a small set of formulas and reading each figure carefully lets you solve these quickly and accurately.

Area and the Pythagorean Theorem

The area of a triangle is one half base times height. In a right triangle, the legs and hypotenuse satisfy a^2 + b^2 = c^2, so legs of 6 and 8 give a hypotenuse of 10. Recognizing common triples (3-4-5, 6-8-10) saves time.

Circles

The area of a circle is pi times the radius squared, and the circumference is 2 pi times the radius. Answers are often left in terms of pi, so a radius of 5 gives an area of 25 pi.

Polygon Angles

The interior angles of a polygon sum to (n - 2) times 180 degrees, where n is the number of sides. A pentagon (n = 5) sums to 540 degrees; dividing by n gives each angle of a regular polygon.

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