Answer:
Length = 8 inches
Width = 15 inches
Explanation:
A rectangular painting has a diagonal measure of 17 inches and an area of 120 square inches. Use the formula for the area of a rectangle and the Pythagorean Theorem to find the length and width of the painting.
Let:
a = length of painting
b = width of painting
Area of painting = 120 = ab
Pythagorean Theorem says
a² + b² = Diagonal²
a² + b²= 17²
[120 =ab means b= 120/a]
a² + (120/a)² = 17²
Multiply through by a²
a⁴ + 14400 = 289
z² + 14400 = 289z [for now, substitute z for a²]
z² - 289z + 14400 = 0
z² - 64z - 225z + 14400 = 0
z(z - 64) -225(z - 64) = 0
(z - 64)(z - 225) = 0
z - 64 = 0
z = 64
z - 225 = 0
z = 225
Note that:
z for a²
Hence:
a² = 64
a = √64
a = 8 inches
The same applies for b
b² = 225
b = √225
b = 15 inches