Question

Difficulty: EasyParallel and Perpendicular Lines

In the standard (x,y)(x, y) coordinate plane, line pp is perpendicular to the line represented by the equation y=0.2x+9y = -0.2x + 9. What is the slope of line pp?

Answer: 5

Answer

The slope of line pp is 55.
The given line is in slope-intercept form y=mx+by = mx + b with a slope of 0.2-0.2, which can be written as 15-\frac{1}{5}. The slope of any line perpendicular to this line is the negative reciprocal of 15-\frac{1}{5}, which is 55.

Step-by-Step Solution

1
Identify the slope of the given line from its equation.
The slope of the line y=0.2x+9y = -0.2x + 9 is 0.2-0.2 (or 15-\frac{1}{5}).
The equation is in slope-intercept form y=mx+by = mx + b, where the coefficient of xx represents the slope mm.
2
Calculate the slope of the perpendicular line.
The negative reciprocal of 15-\frac{1}{5} is 55.
Perpendicular lines have slopes that are negative reciprocals of each other (m1m2=1m_1 \cdot m_2 = -1).

Key Concept

Perpendicular lines in the coordinate plane have slopes that are negative reciprocals of each other.
Estimated Time:45s
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