Free FAA Aviation Mechanic General Practice Test Online

Correct answer: C. 19 °C

Change equals final minus initial: 7−(−12)=19 °C. Crossing zero includes 12 degrees to zero plus 7 more.

• A: Five comes from adding signed values instead of measuring the interval.
• B: Twelve reaches only from −12 to zero.
• D: The temperature increased, so the change is positive rather than negative.

Correct answer: C. 45

Forty-five squared is 45 × 45 = 2,025, so the principal square root of 2,025 is 45. Squaring the selected value verifies the result.

• A: Thirty-five squared is 1,225, which is well below the stated radicand.
• B: Forty squared is 1,600, not the required value of 2,025.
• D: Fifty-five squared is 3,025, which exceeds the stated radicand.

Correct answer: A. 7.2×10⁻⁴

Moving the decimal four places right produces 7.2, so the exponent is −4. Proper scientific notation has one nonzero digit before the decimal.

• B: Seventy-two times 10⁻⁴ equals 0.0072, ten times too large.
• C: A positive exponent gives 72,000 rather than a small decimal.
• D: Zero point seven two times 10⁻⁴ equals 0.000072, ten times too small.

Correct answer: A. 91 in²

Trapezoid area is one-half the sum of parallel sides times height: 0.5×(10+16)×7=91 square inches.

• B: One hundred twelve multiplies only the longer base by height.
• C: One hundred eighty-two omits the one-half factor.
• D: Two hundred twenty-four is twice the rectangle based on the longer side.

Correct answer: B. 15 in

By the Pythagorean theorem, c = √(9² + 12²) = √(81 + 144) = √225 = 15 inches. This applies because the two given legs are perpendicular.

• A: Thirteen is associated with a 5-12-13 triangle, not 9-12.
• C: Eighteen does not satisfy c²=225.
• D: Twenty-one is the sum of the legs, not the diagonal.