Hands-on math!

Washington State Math Olympiad
Hints and Solutions
2015 Grade 5 Geometry

Problem
Hint
1) Determine the total number of squares in this figure. There are squares of 4 different sizes:
l.In terms of small squares:
    4x4, 3x3, 2x2, and 1 small square.
2. Count up the number of squares of each size and add = ____

2) A rectangular wooden box measuring 3 in x 5 in x 7 in is immersed in black paint and then cut into 1 in cubes. What fraction of the resulting cubes will have no paint on any of the faces?
1. Each dimension will be reduced by 2 to count the number of no-paint cubes.
2. Subtract 2 from each dimension and multiply =
    _____ cubes.
3. Total cubes = _____.
4. Fraction = _____

3) A three-dimensional object can be represented by different perspectives: from above (Top view), from the front (Front view), and from the side (typically, Right Side view). This figure shows you an arrangement of cubes. What is the greatest number of cubes that could be in the arrangement shown?
This figure numbers the cube faces for the following discussion:
1. Here are faces that are faces of the same cubes:
  • 1 & 15 (a cube by itself)
  • 2 & 12 (making this the top of a 3-cube stack)
  • 3 & 10 (making this the top of a 2-cube stack)
  • 8 & 13 (making this the top of a 2-cube stack)
2. Put the size of these stacks on the "top" figure.
3. The number of cubes is _____

Problem
Hint
4) The perimeter of a rectangle is 122 feet. The lengths of its sides are whole numbers of feet. What is the greatest area the rectangle can encompass? 1. The greatest area is when the length and the width are close to each other in value.
2. Divide the perimeter by 4 and adjust the length and width until you get whole numbers of feet for both.
3. The length is ____ ft. and the width is ____ ft.
4. Multiply these together to get the area =
    _____ sq. ft.

5) Angle A is 5/9th the measure of angle C.
Find the measure of angle B.
1. (5/9) C = A.
    C = _____
2. Compute B from the other 3 angles of the quadrilateral = _____