Eritrea Grade 8 National Examination flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Area of a circle

The area of a circle equals pi multiplied by the radius squared, written A = πr², where r is the distance from the centre to the edge.

Pythagorean theorem

In any right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c².

Mean of a data set

The mean is calculated by adding all the values in a data set and then dividing that total by the number of values present.

Simple interest formula

Simple interest is principal multiplied by annual rate multiplied by time in years, divided by one hundred: I = PRT/100.

Slope of a line

Slope measures steepness and equals the change in y divided by the change in x between any two points on the line.

Interior angle sum polygon

For a polygon with n sides, the sum of all interior angles is (n − 2) multiplied by 180 degrees.

Probability of an event

Probability equals the number of favourable outcomes divided by the total number of equally likely outcomes, giving a value from zero to one.

Dividing by a fraction

To divide by a fraction, multiply by its reciprocal; for example, a/b ÷ c/d becomes a/b × d/c.

Present perfect tense

The present perfect uses have or has plus a past participle, and it describes an action completed at an unspecified time before now.

Passive voice

In the passive voice the object of an action becomes the subject, and the verb is formed with be plus a past participle.

First conditional sentence

The first conditional describes a likely future result and uses if plus the present simple in one clause, then will plus the base verb.

Comparative adjectives

Short adjectives form the comparative by adding -er, while longer adjectives use the word more before the adjective; than usually follows.

Relative pronoun use

Use who for people, which for things and animals, whose for possession, and where for places when joining clauses.

Topic sentence

A topic sentence states the main idea of a paragraph and is usually the first sentence, with later sentences giving supporting details.

Subject-verb agreement

A singular subject takes a singular verb and a plural subject takes a plural verb; the verb must match its subject in number.

Photosynthesis equation

Photosynthesis uses carbon dioxide and water, with sunlight and chlorophyll, to produce glucose and oxygen: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

Speed formula

Speed is the distance travelled divided by the time taken, commonly written as speed = distance ÷ time and measured in metres per second.

Newton's first law

An object remains at rest or moves at constant velocity unless a net external force acts on it; this is also called inertia.

Density formula

Density equals mass divided by volume, written d = m/V, and is usually expressed in grams per cubic centimetre or kilograms per cubic metre.

Series and parallel circuits

In a series circuit the current is the same through every component, while in a parallel circuit the voltage is the same across each branch.

Acid and base indicators

Acids turn blue litmus paper red, bases turn red litmus paper blue, and pH values below seven indicate acids while values above seven indicate bases.

Cell organelles

The nucleus controls cell activities, mitochondria release energy through respiration, and chloroplasts carry out photosynthesis in plant cells.

Food chain order

A food chain begins with a producer, followed by primary and secondary consumers; energy decreases at each higher level.

Eritrea independence year

Eritrea became an independent nation in 1993, and its capital city is Asmara, located in the central highlands.

Eritrea neighbouring countries

Eritrea borders Sudan to the west, Ethiopia to the south, Djibouti to the southeast, and the Red Sea to the east.

Lines of latitude

Lines of latitude run east to west, are parallel, and measure distance north or south of the Equator in degrees.

Map scale meaning

A map scale such as 1:50,000 means one centimetre on the map represents 50,000 centimetres, or half a kilometre, on the ground.

Three branches of government

Government power is usually divided into the executive, which implements laws; the legislature, which makes laws; and the judiciary, which interprets laws.

Rain shadow effect

A rain shadow is the dry area on the leeward side of a mountain because moist air rises and rains on the windward side, then descends and warms.

Complete sentence

A complete sentence contains a subject and a predicate and expresses a complete thought; a fragment lacks one of these essential parts.

Direct and indirect speech

Direct speech repeats a speaker's exact words inside quotation marks, while indirect speech reports the meaning without quotation marks and usually shifts the tense.

Synonyms and antonyms

Synonyms are words with similar meanings, such as big and large, while antonyms are words with opposite meanings, such as hot and cold.