Re: Which of the following statements, considered independently,
[#permalink]
11 Jun 2021, 22:36
A,B only.
If angle ACB = 90°, then 8 and
15 are the base and height, and you can calculate the area. The first statement
is sufficient.
If AB = 17, you can plug 8, 15, and 17 into the Pythagorean theorem to see
whether you get a true statement. Use 17 as the hypotenuse in the
Pythagorean theorem because 17 is the longest side:
(8)2 + (15)2 = (17)2
64 + 225 = 289
289 = 289
Since this is true, the triangle is a right triangle with the right angle at C. If
angle ACB = 90°, then 8 and 15 are the base and height, and you can calculate
the area. (Since 8–15–17 is a Pythagorean triple, if you had that fact
memorized, you could skip the step above.) The second statement is
sufficient.
Knowing that ABC is a right triangle (the third statement) is not sufficient to
calculate the area because it’s not specified which angle is the right angle. A
triangle with sides of 8 and 15 could have hypotenuse 17, but another
scenario is possible: perhaps 15 is the hypotenuse. In this case, the third side
is shorter than 15, and the area is smaller than in the 8–15–17 scenario.