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Zorluk: OrtaScale Drawings and Map Measurements

A naval architect creates a scale drawing for a new submarine. The drawing uses a scale of 316 inch=15 feet\frac{3}{16}\text{ inch} = 15\text{ feet}. If the pressure hull measures 418 inches4\frac{1}{8}\text{ inches} long on the drawing, what is the actual length, in feet, of the pressure hull?

Cevap: 330 feet

Cevap

330
The scale establishes that every inch on the drawing represents 8080 actual feet (15÷316=8015 \div \frac{3}{16} = 80). Multiplying the drawing length of 4184\frac{1}{8} inches (or 338\frac{33}{8} inches) by 8080 feet per inch yields the correct actual length of 330330 feet.

Adım Adım Çözüm

1
Find the unit rate for 1 inch1\text{ inch} of the drawing.
15÷316=15×163=5×16=80 feet15 \div \frac{3}{16} = 15 \times \frac{16}{3} = 5 \times 16 = 80\text{ feet} per inch.
Establishing a unit rate simplifies finding actual dimensions for any measurement on the scale drawing.
2
Convert the drawing measurement from a mixed number to an improper fraction.
418=4×8+18=338 inches4\frac{1}{8} = \frac{4 \times 8 + 1}{8} = \frac{33}{8}\text{ inches}.
Improper fractions are required to properly multiply the scale factor with the drawing measurement.
3
Calculate the actual length by multiplying the map measurement by the unit rate.
338×80=33×10=330 feet\frac{33}{8} \times 80 = 33 \times 10 = 330\text{ feet}.
Multiplying the measurement on the drawing by the actual distance per inch yields the total actual distance.

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Scale Drawings and Map Measurements
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