HiSET: Math : Solve problems

Study concepts, example questions & explanations for HiSET: Math

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Example Questions

Example Question #1 : Measurement And Geometry

Two of the angles of a triangle are congruent; the third has measure ten degrees greater than either one of the first two. What is the measure of the third angle?

Possible Answers:

\(\displaystyle 66 \frac{2}{3} ^{\circ }\)

\(\displaystyle 56 \frac{2}{3} ^{\circ }\)

\(\displaystyle 73\frac{1}{3}^{\circ }\)

\(\displaystyle 63 \frac{1}{3} ^{\circ }\)

\(\displaystyle 53 \frac{1}{3} ^{\circ }\)

Correct answer:

\(\displaystyle 66 \frac{2}{3} ^{\circ }\)

Explanation:

Let \(\displaystyle x\) be the measure of the third angle. Since its measure is ten degrees greater than either of the others, then the common measure of the other two is \(\displaystyle x- 10\). The sum of the measures of the angles of a triangle is 180 degrees, so

\(\displaystyle x+ (x-10) + (x-10) = 180\)

To solve for \(\displaystyle x\), first ungroup and collect like terms:

\(\displaystyle x+ x - 10 + x - 10 = 180\)

\(\displaystyle x+ x + x - 10 - 10 = 180\)

\(\displaystyle 3x - 20 = 180\)

Isolate \(\displaystyle x\); first add 20:

\(\displaystyle 3x-20+20 = 180 + 20\)

\(\displaystyle 3x= 200\)

Divide by 3:

\(\displaystyle 3x \div 3 = 200 \div 3\)

Since \(\displaystyle 200 \div 3 = 66 \textup{ R }2\),

\(\displaystyle x = 66 \frac{2}{3}\).

The third angle measures \(\displaystyle 66 \frac{2}{3} ^{\circ }\).

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