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McGraw-Hill Math Grade 7 Answer Key Lesson 18.5 Area
Exercises
SOLVE
Question 1.
How many people can you allow on a beach if the lifeguards want to have 20 sq ft per person and the beach is 1,000 ft long and 200 ft wide? Round to a whole number.
Answer:
Number of people can be allow on a beach = 10,000.
Explanation:
Length of the beach = 1,000 ft.
Width of the beach = 200 ft.
Area of the beach = Length of the beach × Width of the beach
= 1,000 × 200
= 2,00,000 square feet.
Number of square feet each person wants = 20 square feet.
Number of people can be allow on a beach = Area of the beach ÷ Number of square feet each person wants
= 2,00,000 ÷ 20
= 10,000.
Question 2.
A square that has sides of 25 ft is split in half down the middle. What is the area of each of the pieces?
Answer:
Area of each of the piece = 312.5 square feet.
Explanation:
Side of the square = 25 ft.
A square that has sides of 25 ft is split in half down the middle.
Area of each of the piece = \(\frac{1}{2}\) × Side of the square × Side of the square
= \(\frac{1}{2}\) × 25 × 25
= \(\frac{1}{2}\) × 625
= 312.5 square feet.
Question 3.
A right triangle has a base of 24 feet and a height of 7 feet. What is its area?
Answer:
Area of the right triangle = 84 square feet.
Explanation:
Base of the right triangle = 24 feet.
Height of the right triangle = 7 feet.
Area of the right triangle = \(\frac{1}{2}\) × Base of the right triangle × Height of the right triangle
= \(\frac{1}{2}\) × 24 × 7
= \(\frac{1}{1}\) × 12 × 7
= 84 square feet.
Question 4.
Which has a larger area, a triangle with a base of 15 ft and a height of 25 ft or a square with sides of 14 ft?
Answer:
Square has a larger area than a triangle with a base of 15 ft and a height of 25 ft.
Explanation:
Base of the triangle = 15 feet.
Height of the triangle = 25 feet.
Area of the triangle = \(\frac{1}{2}\) × Base of the triangle × Height of the triangle
= \(\frac{1}{2}\) × 15 × 25
= \(\frac{1}{2}\) × 375
= 187.5 square feet.
Side of the square = 14 feet.
Area of the square = Side of the square × Side of the square
= 14 × 14
= 196 square feet.